2025 day 10 part 2 in Rust

Using a library. I'm not happy about it but also I have thought about
this enough.

.github/workflows/2024.yml

@@ -1,43 +0,0 @@
-on:
-  - push
-
-name: Advent of Code 2024
-
-jobs:
-  ci:
-    strategy:
-      matrix:
-        python-version:
-          - "3.12"
-          - "3.13"
-
-    name: Continuous Integration
-    runs-on: ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v4
-
-      - uses: actions/setup-python@v5
-        with:
-          python-version: ${{ matrix.python-version }}
-
-      - name: Install uv
-        uses: astral-sh/setup-uv@v3
-        with:
-          enable-cache: true
-          cache-dependency-glob: "2024/uv.lock"
-
-      - name: Check formatting
-        working-directory: "2024"
-        run: >
-          uv run ruff format --check
-
-      - name: Run lints
-        working-directory: "2024"
-        run: >
-          uv run ruff check
-
-      - name: Run tests
-        working-directory: "2024"
-        run: >
-          uv run pytest tests

2024/bonus/24todot.py

@@ -0,0 +1,15 @@
+import fileinput
+
+print("digraph day24 {")
+
+for line in fileinput.input():
+    parts = line.split(" ")
+    if len(parts) != 5:
+        continue
+
+    first, op, second, _, result = parts
+    print(f'{first}{second}{op} [label="{op}"];')
+    print(f"{first} -> {first}{second}{op} -> {result};")
+    print(f"{second} -> {first}{second}{op};")
+
+print("}")

2024/bonus/day01/main.tf

@@ -6,8 +6,8 @@ locals {
   cleaned_input = replace(var.input, "/ +/", " ")
   lines         = split("\n", trim(local.cleaned_input, "\n"))
   lines_split   = [for line in local.lines : split(" ", line)]
-  left          = [for line in local.lines_split : parseint(line[0], 10)]
-  right         = [for line in local.lines_split : parseint(line[1], 10)]
+  left          = [for line in local.lines_split : tonumber(line[0])]
+  right         = [for line in local.lines_split : tonumber(line[1])]
 
   left_sorted  = sort(local.left)
   right_sorted = sort(local.right)

2024/bonus/day02/main.tf

@@ -3,7 +3,7 @@ variable "input" {
 }
 
 locals {
-  reports = [for line in split("\n", trim(var.input, "\n")) : [for num in split(" ", line) : parseint(num, 10)]]
+  reports = [for line in split("\n", trim(var.input, "\n")) : split(" ", line)]
 }
 
 module "part1_valid" {

2024/bonus/day05/is_correct/main.tf

@@ -1,21 +0,0 @@
-variable "update" {
-  type = list(number)
-}
-
-variable "disallow_rules" {
-  type = map(list(number))
-}
-
-locals {
-  not_disallowed = alltrue([
-    for i in range(1, length(var.update)) :
-    !contains(
-      flatten([for j in range(i) : lookup(var.disallow_rules, var.update[j], [])]),
-      var.update[i]
-    )
-  ])
-}
-
-output "valid" {
-  value = local.not_disallowed ? var.update[floor(length(var.update) / 2)] : 0
-}

2024/bonus/day05/main.tf

@@ -8,16 +8,18 @@ locals {
   disallow_rules = { for rule in local.rules : rule[1] => rule[0]... }
 
   updates = [for update_line in split("\n", local.parts[1]) : [for v in split(",", update_line) : tonumber(v)]]
-}
 
-module "is_valid" {
-  source = "./is_correct"
-  count  = length(local.updates)
-
-  update         = local.updates[count.index]
-  disallow_rules = local.disallow_rules
+  scores = [
+    for update in local.updates :
+    alltrue([
+      for i in range(1, length(update)) :
+      !contains(
+        flatten([for j in range(i) : lookup(local.disallow_rules, update[j], [])]),
+        update[i]
+      )
+  ]) ? update[floor(length(update) / 2)] : 0]
 }
 
 output "part1" {
-  value = sum(module.is_valid[*].valid)
+  value = sum(local.scores[*])
 }

2024/bonus/day08/freq/main.tf

@@ -0,0 +1,52 @@
+variable "width" {
+  type = number
+}
+
+variable "height" {
+  type = number
+}
+
+variable "antennae" {
+  type = list(tuple([number, number]))
+}
+
+locals {
+  pairs = concat([
+    for i in range(length(var.antennae)) :
+    [
+      for j in range(i + 1, length(var.antennae)) : [var.antennae[i], var.antennae[j]]
+    ]
+  ]...)
+}
+
+module "pair" {
+  source = "./pair"
+  count  = length(local.pairs)
+
+  first  = local.pairs[count.index][0]
+  second = local.pairs[count.index][1]
+  width  = var.width
+  height = var.height
+}
+
+output "nodes1" {
+  value = setunion([
+    for i in range(length(local.pairs)) :
+    [
+      for v in module.pair[i].nodes1 :
+      v
+      if v[0] >= 0 && v[0] < var.width && v[1] >= 0 && v[1] < var.height
+    ]
+  ]...)
+}
+
+output "nodes2" {
+  value = setunion([
+    for i in range(length(local.pairs)) :
+    [
+      for v in module.pair[i].nodes2 :
+      v
+      if v[0] >= 0 && v[0] < var.width && v[1] >= 0 && v[1] < var.height
+    ]
+  ]...)
+}

2024/bonus/day08/freq/pair/main.tf

@@ -0,0 +1,52 @@
+variable "first" {
+  type = tuple([number, number])
+}
+
+variable "second" {
+  type = tuple([number, number])
+}
+
+variable "width" {
+  type = number
+}
+
+variable "height" {
+  type = number
+}
+
+locals {
+  dx = var.second[0] - var.first[0]
+  dy = var.second[1] - var.first[1]
+
+  # sort() doesn't work as it turns the numbers into strings
+  gcd0 = abs(local.dx) < abs(local.dy) ? [abs(local.dx), abs(local.dy)] : [abs(local.dy), abs(local.dx)]
+
+  # Do as many iterations as necessary. 
+  gcd1  = local.gcd0[0] == 0 ? local.gcd0 : [local.gcd0[1] % local.gcd0[0], local.gcd0[0]]
+  gcd2  = local.gcd1[0] == 0 ? local.gcd1 : [local.gcd1[1] % local.gcd1[0], local.gcd1[0]]
+  gcd3  = local.gcd2[0] == 0 ? local.gcd2 : [local.gcd2[1] % local.gcd2[0], local.gcd2[0]]
+  gcd4  = local.gcd3[0] == 0 ? local.gcd3 : [local.gcd3[1] % local.gcd3[0], local.gcd3[0]]
+  gcd5  = local.gcd4[0] == 0 ? local.gcd4 : [local.gcd4[1] % local.gcd4[0], local.gcd4[0]]
+  gcd6  = local.gcd5[0] == 0 ? local.gcd5 : [local.gcd5[1] % local.gcd5[0], local.gcd5[0]]
+  gcd7  = local.gcd6[0] == 0 ? local.gcd6 : [local.gcd6[1] % local.gcd6[0], local.gcd6[0]]
+  gcd8  = local.gcd7[0] == 0 ? local.gcd7 : [local.gcd7[1] % local.gcd7[0], local.gcd7[0]]
+  gcd9  = local.gcd8[0] == 0 ? local.gcd8 : [local.gcd8[1] % local.gcd8[0], local.gcd8[0]]
+  gcd10 = local.gcd9[0] == 0 ? local.gcd9 : [local.gcd9[1] % local.gcd9[0], local.gcd9[0]]
+
+  # 10 iterations should cover numbers up to 55, which is more than the width/height
+  gcd = local.gcd10[1]
+}
+
+output "nodes1" {
+  value = [
+    [var.first[0] - local.dx, var.first[1] - local.dy],
+    [var.second[0] + local.dx, var.second[1] + local.dy],
+  ]
+}
+
+output "nodes2" {
+  value = concat(
+    [for i in range(max(var.width, var.height)) : [var.first[0] - i * local.dx / local.gcd, var.first[1] - i * local.dy / local.gcd]],
+    [for i in range(max(var.width, var.height)) : [var.second[0] + i * local.dx / local.gcd, var.second[1] + i * local.dy / local.gcd]]
+  )
+}

2024/bonus/day08/main.tf

@@ -0,0 +1,39 @@
+variable "input" {
+  type = string
+}
+
+locals {
+  lines  = split("\n", chomp(var.input))
+  height = length(local.lines)
+  width  = length(local.lines[0])
+
+  antennae = concat([
+    for y in range(local.height) :
+    [
+      for x in range(local.width) :
+      [substr(local.lines[y], x, 1), x, y]
+      if substr(local.lines[y], x, 1) != "."
+    ]
+  ]...)
+
+  by_freq = {
+    for antenna in local.antennae :
+    antenna[0] => [antenna[1], antenna[2]]...
+  }
+}
+
+module "freq" {
+  source   = "./freq"
+  for_each = local.by_freq
+  width    = local.width
+  height   = local.height
+  antennae = each.value
+}
+
+output "part1" {
+  value = length(setunion([for _, v in module.freq : v.nodes1]...))
+}
+
+output "part2" {
+  value = length(setunion([for _, v in module.freq : v.nodes2]...))
+}

2024/bonus/day11/main.tf

@@ -15,150 +15,10 @@ module "step1" {
   prev = local.total
 }
 
-module "step2" {
-  source = "./step"
-
-  prev = module.step1.next
-}
-
-module "step3" {
-  source = "./step"
-
-  prev = module.step2.next
-}
-
-module "step4" {
-  source = "./step"
-
-  prev = module.step3.next
-}
-
-module "step5" {
-  source = "./step"
-
-  prev = module.step4.next
-}
-
-module "step6" {
-  source = "./step"
-
-  prev = module.step5.next
-}
-
-module "step7" {
-  source = "./step"
-
-  prev = module.step6.next
-}
-
-module "step8" {
-  source = "./step"
-
-  prev = module.step7.next
-}
-
-module "step9" {
-  source = "./step"
-
-  prev = module.step8.next
-}
-
-module "step10" {
-  source = "./step"
-
-  prev = module.step9.next
-}
-
-module "step11" {
-  source = "./step"
-
-  prev = module.step10.next
-}
-
-module "step12" {
-  source = "./step"
-
-  prev = module.step11.next
-}
-
-module "step13" {
-  source = "./step"
-
-  prev = module.step12.next
-}
-
-module "step14" {
-  source = "./step"
-
-  prev = module.step13.next
-}
-
-module "step15" {
-  source = "./step"
-
-  prev = module.step14.next
-}
-
-module "step16" {
-  source = "./step"
-
-  prev = module.step15.next
-}
-
-module "step17" {
-  source = "./step"
-
-  prev = module.step16.next
-}
-
-module "step18" {
-  source = "./step"
-
-  prev = module.step17.next
-}
-
-module "step19" {
-  source = "./step"
-
-  prev = module.step18.next
-}
-
-module "step20" {
-  source = "./step"
-
-  prev = module.step19.next
-}
-
-module "step21" {
-  source = "./step"
-
-  prev = module.step20.next
-}
-
-module "step22" {
-  source = "./step"
-
-  prev = module.step21.next
-}
-
-module "step23" {
-  source = "./step"
-
-  prev = module.step22.next
-}
-
-module "step24" {
-  source = "./step"
-
-  prev = module.step23.next
-}
-
-module "step25" {
-  source = "./step"
-
-  prev = module.step24.next
-}
-
 output "part1" {
   value = sum(values(module.step25.next))
 }
+
+output "part2" {
+  value = sum(values(module.step75.next))
+}

2024/bonus/day11/step/main.tf

@@ -2,33 +2,31 @@ variable "prev" {
   type = map(number)
 }
 
-module "transform" {
-  source   = "../transform"
-  for_each = var.prev
-
-  num = each.key
-}
-
 locals {
   by_value = flatten([
-    for key, value in module.transform :
-    [for result in value.result : { num = result, count = var.prev[key] }]
+    for num, count in var.prev : (
+      tonumber(num) == 0
+      ? [{ number = 1, amount = count }]
+      : (
+        length(tostring(num)) % 2 == 0
+        ? [
+          {
+            number = tonumber(substr(tostring(num), 0, length(tostring(num)) / 2)),
+            amount = count
+          },
+          {
+            number = tonumber(substr(tostring(num), length(tostring(num)) / 2, length(tostring(num)) / 2)),
+            amount = count,
+          },
+        ]
+        : [{ number = 2024 * num, amount = count }]
+      )
+    )
   ])
 
-  grouped = { for kv in local.by_value : kv.num => kv.count... }
+  grouped = { for kv in local.by_value : kv.number => kv.amount... }
 }
 
-# module "transform" {
-#   source = "../transform"
-
-#   count = length(var.prev)
-#   num   = var.prev[count.index]
-# }
-
-# output "next" {
-#   value = flatten(module.transform[*].result)
-# }
-
 output "next" {
   value = { for num, groups in local.grouped : num => sum(groups) }
 }

2024/bonus/day11/steps.tf

@@ -0,0 +1,446 @@
+# This file was generated using a nasty bash for loop. Edit at your own peril.  
+
+module "step2" {
+  source = "./step"
+
+  prev = module.step1.next
+}
+
+module "step3" {
+  source = "./step"
+
+  prev = module.step2.next
+}
+
+module "step4" {
+  source = "./step"
+
+  prev = module.step3.next
+}
+
+module "step5" {
+  source = "./step"
+
+  prev = module.step4.next
+}
+
+module "step6" {
+  source = "./step"
+
+  prev = module.step5.next
+}
+
+module "step7" {
+  source = "./step"
+
+  prev = module.step6.next
+}
+
+module "step8" {
+  source = "./step"
+
+  prev = module.step7.next
+}
+
+module "step9" {
+  source = "./step"
+
+  prev = module.step8.next
+}
+
+module "step10" {
+  source = "./step"
+
+  prev = module.step9.next
+}
+
+module "step11" {
+  source = "./step"
+
+  prev = module.step10.next
+}
+
+module "step12" {
+  source = "./step"
+
+  prev = module.step11.next
+}
+
+module "step13" {
+  source = "./step"
+
+  prev = module.step12.next
+}
+
+module "step14" {
+  source = "./step"
+
+  prev = module.step13.next
+}
+
+module "step15" {
+  source = "./step"
+
+  prev = module.step14.next
+}
+
+module "step16" {
+  source = "./step"
+
+  prev = module.step15.next
+}
+
+module "step17" {
+  source = "./step"
+
+  prev = module.step16.next
+}
+
+module "step18" {
+  source = "./step"
+
+  prev = module.step17.next
+}
+
+module "step19" {
+  source = "./step"
+
+  prev = module.step18.next
+}
+
+module "step20" {
+  source = "./step"
+
+  prev = module.step19.next
+}
+
+module "step21" {
+  source = "./step"
+
+  prev = module.step20.next
+}
+
+module "step22" {
+  source = "./step"
+
+  prev = module.step21.next
+}
+
+module "step23" {
+  source = "./step"
+
+  prev = module.step22.next
+}
+
+module "step24" {
+  source = "./step"
+
+  prev = module.step23.next
+}
+
+module "step25" {
+  source = "./step"
+
+  prev = module.step24.next
+}
+
+module "step26" {
+  source = "./step"
+
+  prev = module.step25.next
+}
+
+module "step27" {
+  source = "./step"
+
+  prev = module.step26.next
+}
+
+module "step28" {
+  source = "./step"
+
+  prev = module.step27.next
+}
+
+module "step29" {
+  source = "./step"
+
+  prev = module.step28.next
+}
+
+module "step30" {
+  source = "./step"
+
+  prev = module.step29.next
+}
+
+module "step31" {
+  source = "./step"
+
+  prev = module.step30.next
+}
+
+module "step32" {
+  source = "./step"
+
+  prev = module.step31.next
+}
+
+module "step33" {
+  source = "./step"
+
+  prev = module.step32.next
+}
+
+module "step34" {
+  source = "./step"
+
+  prev = module.step33.next
+}
+
+module "step35" {
+  source = "./step"
+
+  prev = module.step34.next
+}
+
+module "step36" {
+  source = "./step"
+
+  prev = module.step35.next
+}
+
+module "step37" {
+  source = "./step"
+
+  prev = module.step36.next
+}
+
+module "step38" {
+  source = "./step"
+
+  prev = module.step37.next
+}
+
+module "step39" {
+  source = "./step"
+
+  prev = module.step38.next
+}
+
+module "step40" {
+  source = "./step"
+
+  prev = module.step39.next
+}
+
+module "step41" {
+  source = "./step"
+
+  prev = module.step40.next
+}
+
+module "step42" {
+  source = "./step"
+
+  prev = module.step41.next
+}
+
+module "step43" {
+  source = "./step"
+
+  prev = module.step42.next
+}
+
+module "step44" {
+  source = "./step"
+
+  prev = module.step43.next
+}
+
+module "step45" {
+  source = "./step"
+
+  prev = module.step44.next
+}
+
+module "step46" {
+  source = "./step"
+
+  prev = module.step45.next
+}
+
+module "step47" {
+  source = "./step"
+
+  prev = module.step46.next
+}
+
+module "step48" {
+  source = "./step"
+
+  prev = module.step47.next
+}
+
+module "step49" {
+  source = "./step"
+
+  prev = module.step48.next
+}
+
+module "step50" {
+  source = "./step"
+
+  prev = module.step49.next
+}
+
+module "step51" {
+  source = "./step"
+
+  prev = module.step50.next
+}
+
+module "step52" {
+  source = "./step"
+
+  prev = module.step51.next
+}
+
+module "step53" {
+  source = "./step"
+
+  prev = module.step52.next
+}
+
+module "step54" {
+  source = "./step"
+
+  prev = module.step53.next
+}
+
+module "step55" {
+  source = "./step"
+
+  prev = module.step54.next
+}
+
+module "step56" {
+  source = "./step"
+
+  prev = module.step55.next
+}
+
+module "step57" {
+  source = "./step"
+
+  prev = module.step56.next
+}
+
+module "step58" {
+  source = "./step"
+
+  prev = module.step57.next
+}
+
+module "step59" {
+  source = "./step"
+
+  prev = module.step58.next
+}
+
+module "step60" {
+  source = "./step"
+
+  prev = module.step59.next
+}
+
+module "step61" {
+  source = "./step"
+
+  prev = module.step60.next
+}
+
+module "step62" {
+  source = "./step"
+
+  prev = module.step61.next
+}
+
+module "step63" {
+  source = "./step"
+
+  prev = module.step62.next
+}
+
+module "step64" {
+  source = "./step"
+
+  prev = module.step63.next
+}
+
+module "step65" {
+  source = "./step"
+
+  prev = module.step64.next
+}
+
+module "step66" {
+  source = "./step"
+
+  prev = module.step65.next
+}
+
+module "step67" {
+  source = "./step"
+
+  prev = module.step66.next
+}
+
+module "step68" {
+  source = "./step"
+
+  prev = module.step67.next
+}
+
+module "step69" {
+  source = "./step"
+
+  prev = module.step68.next
+}
+
+module "step70" {
+  source = "./step"
+
+  prev = module.step69.next
+}
+
+module "step71" {
+  source = "./step"
+
+  prev = module.step70.next
+}
+
+module "step72" {
+  source = "./step"
+
+  prev = module.step71.next
+}
+
+module "step73" {
+  source = "./step"
+
+  prev = module.step72.next
+}
+
+module "step74" {
+  source = "./step"
+
+  prev = module.step73.next
+}
+
+module "step75" {
+  source = "./step"
+
+  prev = module.step74.next
+}
+

2024/bonus/day11/transform/main.tf

@@ -1,15 +0,0 @@
-variable "num" {
-  type = number
-}
-
-locals {
-  as_str = tostring(var.num)
-  len    = length(local.as_str)
-  half   = floor(length(local.as_str) / 2)
-  first  = try(tonumber(substr(local.as_str, 0, local.half)), -1)
-  second = try(tonumber(substr(local.as_str, local.half, local.half)), -1)
-}
-
-output "result" {
-  value = var.num == 0 ? [1] : local.len % 2 == 0 ? [local.first, local.second] : [var.num * 2024]
-}

2024/bonus/day13/main.tf

@@ -0,0 +1,31 @@
+variable "input" {
+  type = string
+}
+
+locals {
+  machines = regexall(
+    "Button A: X\\+(\\d+), Y\\+(\\d+)\nButton B: X\\+(\\d+), Y\\+(\\d+)\nPrize: X=(\\d+), Y=(\\d+)",
+    var.input
+  )
+}
+
+module "solve1" {
+  source   = "./solve"
+  machines = local.machines
+}
+
+module "solve2" {
+  source = "./solve"
+  machines = [
+    for machine in local.machines :
+    [machine[0], machine[1], machine[2], machine[3], 10000000000000 + machine[4], 10000000000000 + machine[5]]
+  ]
+}
+
+output "part1" {
+  value = module.solve1.solutions
+}
+
+output "part2" {
+  value = module.solve2.solutions
+}

2024/bonus/day13/solve/main.tf

@@ -0,0 +1,34 @@
+variable "machines" {
+  type = list(list(number))
+}
+
+locals {
+  a_substitutions = [
+    for machine in var.machines :
+    [-machine[2] / machine[0], machine[4] / machine[0]]
+  ]
+
+  b_equations = [
+    for i in range(length(var.machines)) :
+    [
+      var.machines[i][3] + local.a_substitutions[i][0] * var.machines[i][1],
+      var.machines[i][5] - local.a_substitutions[i][1] * var.machines[i][1]
+    ]
+  ]
+
+  b = [for eq in local.b_equations : floor(eq[1] / eq[0] + 0.5)]
+
+  a = [
+    for i in range(length(var.machines)) :
+    floor((var.machines[i][4] - local.b[i] * var.machines[i][2]) / var.machines[i][0] + 0.5)
+  ]
+}
+
+output "solutions" {
+  value = sum([
+    for i in range(length(var.machines)) :
+    3 * local.a[i] + local.b[i]
+    if var.machines[i][0] * local.a[i] + var.machines[i][2] * local.b[i] == var.machines[i][4]
+    && var.machines[i][1] * local.a[i] + var.machines[i][3] * local.b[i] == var.machines[i][5]
+  ])
+}

2024/bonus/day14/main.tf

@@ -0,0 +1,33 @@
+variable "input" {
+  type = string
+}
+
+variable "width" {
+  type    = number
+  default = 101
+}
+
+variable "height" {
+  type    = number
+  default = 103
+}
+
+locals {
+  lines = regexall("p=(-?\\d+),(-?\\d+) v=(-?\\d+),(-?\\d+)", var.input)
+  positions = [
+    for line in local.lines :
+    [
+      ((line[0] + 100 * line[2]) % var.width + var.width) % var.width,
+      ((line[1] + 100 * line[3]) % var.height + var.height) % var.height,
+    ]
+  ]
+
+  q1 = length([for pos in local.positions : pos if pos[0] < floor(var.width / 2) && pos[1] < floor(var.height / 2)])
+  q2 = length([for pos in local.positions : pos if pos[0] > floor(var.width / 2) && pos[1] < floor(var.height / 2)])
+  q3 = length([for pos in local.positions : pos if pos[0] < floor(var.width / 2) && pos[1] > floor(var.height / 2)])
+  q4 = length([for pos in local.positions : pos if pos[0] > floor(var.width / 2) && pos[1] > floor(var.height / 2)])
+}
+
+output "part1" {
+  value = local.q1 * local.q2 * local.q3 * local.q4
+}

2024/bonus/day19/main.tf

@@ -0,0 +1,13 @@
+variable "input" {
+  type = string
+}
+
+locals {
+  parts    = split("\n\n", chomp((var.input)))
+  patterns = replace(local.parts[0], ", ", "|")
+  valid    = [for line in split("\n", local.parts[1]) : line if length(regexall("^(${local.patterns})+$", line)) > 0]
+}
+
+output "part1" {
+  value = length(local.valid)
+}

2024/bonus/day25/main.tf

@@ -0,0 +1,23 @@
+variable "input" {
+  type = string
+}
+
+locals {
+  blocks = split("\n\n", chomp(var.input))
+  heights = [
+    for block in local.blocks : [
+      for i in range(5) : length([
+        for line in split("\n", block) : line if substr(line, i, 1) == "#"
+      ])
+    ]
+  ]
+
+  locks = [for i in range(length(local.blocks)) : local.heights[i] if startswith(local.blocks[i], "#####")]
+  keys  = [for i in range(length(local.blocks)) : local.heights[i] if !startswith(local.blocks[i], "#####")]
+
+  combined = concat([for lock in local.locks : [for key in local.keys : [for i in range(5) : lock[i] + key[i] <= 7]]]...)
+}
+
+output "part1" {
+  value = length([for combination in local.combined : combination if alltrue(combination)])
+}

2024/bonus/main.tf

@@ -66,6 +66,19 @@ output "day05_1" {
   value = module.day05.part1
 }
 
+module "day08" {
+  source = "./day08"
+  input  = file("../inputs/08.txt")
+}
+
+output "day08_1" {
+  value = module.day08.part1
+}
+
+output "day08_2" {
+  value = module.day08.part2
+}
+
 module "day11" {
   source = "./day11"
   input  = file("../inputs/11.txt")
@@ -74,3 +87,47 @@ module "day11" {
 output "day11_1" {
   value = module.day11.part1
 }
+
+output "day11_2" {
+  value = module.day11.part2
+}
+
+module "day13" {
+  source = "./day13"
+  input  = file("../inputs/13.txt")
+}
+
+output "day13_1" {
+  value = module.day13.part1
+}
+
+output "day13_2" {
+  value = module.day13.part2
+}
+
+module "day14" {
+  source = "./day14"
+  input  = file("../inputs/14.txt")
+}
+
+output "day14_1" {
+  value = module.day14.part1
+}
+
+module "day19" {
+  source = "./day19"
+  input  = file("../inputs/19.txt")
+}
+
+output "day19_1" {
+  value = module.day19.part1
+}
+
+module "day25" {
+  source = "./day25"
+  input  = file("../inputs/25.txt")
+}
+
+output "day25_1" {
+  value = module.day25.part1
+}

2024/bonus/tests.tftest.hcl

@@ -131,6 +131,29 @@ run "day5_1" {
   }
 }
 
+run "day08" {
+  command = plan
+
+  module {
+    source = "./day08"
+  }
+
+  variables {
+    input = file("../tests/samples/08.txt")
+  }
+
+  assert {
+    condition     = output.part1 == 14
+    error_message = "Part1 output is wrong"
+  }
+
+
+  assert {
+    condition     = output.part2 == 34
+    error_message = "Part1 output is wrong"
+  }
+}
+
 run "day11" {
   command = plan
 
@@ -146,5 +169,74 @@ run "day11" {
     condition     = output.part1 == 55312
     error_message = "Part1 output is wrong"
   }
-
+}
+
+run "day13" {
+  command = plan
+
+  module {
+    source = "./day13"
+  }
+
+  variables {
+    input = file("../tests/samples/13.txt")
+  }
+
+  assert {
+    condition     = output.part1 == 480
+    error_message = "Part1 output is wrong"
+  }
+}
+
+run "day14" {
+  command = plan
+
+  module {
+    source = "./day14"
+  }
+
+  variables {
+    input  = file("../tests/samples/14.txt")
+    height = 7
+    width  = 11
+  }
+
+  assert {
+    condition     = output.part1 == 12
+    error_message = "Part1 output is wrong"
+  }
+}
+
+run "day19" {
+  command = plan
+
+  module {
+    source = "./day19"
+  }
+
+  variables {
+    input = file("../tests/samples/19.txt")
+  }
+
+  assert {
+    condition     = output.part1 == 6
+    error_message = "Part1 output is wrong"
+  }
+}
+
+run "day25" {
+  command = plan
+
+  module {
+    source = "./day25"
+  }
+
+  variables {
+    input = file("../tests/samples/25.txt")
+  }
+
+  assert {
+    condition     = output.part1 == 3
+    error_message = "Part1 output is wrong"
+  }
 }

2024/pyproject.toml

@@ -6,6 +6,7 @@ readme = "README.md"
 requires-python = ">=3.12"
 dependencies = [
     "click>=8.1.7",
+    "networkx>=3.4.2",
     "numpy>=2.1.2",
 ]
 

2024/src/aoc/days/day12.py

@@ -0,0 +1,101 @@
+import numpy
+
+from . import CombinedRunner
+
+DIRECTIONS = [
+    (-1, 0),
+    (1, 0),
+    (0, -1),
+    (0, 1),
+]
+
+
+class DayRunner(CombinedRunner):
+    @classmethod
+    def run_both(cls, input: str) -> tuple[int, int]:
+        grid = numpy.array(list(map(list, input.strip().split("\n"))))
+
+        score = 0
+        score2 = 0
+
+        for y in range(grid.shape[0]):
+            for x in range(grid.shape[1]):
+                if grid[y, x] == ".":
+                    continue
+
+                search = grid[y, x]
+                grid[y, x] = "."
+
+                todo = [(y, x)]
+                cluster = {(y, x)}
+
+                def enqueue(y, x):
+                    if grid[y, x] == search:
+                        grid[y, x] = "."
+                        todo.append((y, x))
+                        cluster.add((y, x))
+
+                while todo:
+                    cy, cx = todo.pop()
+
+                    if cx > 0:
+                        enqueue(cy, cx - 1)
+                    if cy > 0:
+                        enqueue(cy - 1, cx)
+
+                    if cx < grid.shape[1] - 1:
+                        enqueue(cy, cx + 1)
+                    if cy < grid.shape[0] - 1:
+                        enqueue(cy + 1, cx)
+
+                side_length = sum(
+                    sum((cy + dy, cx + dx) not in cluster for dy, dx in DIRECTIONS)
+                    for cy, cx in cluster
+                )
+
+                corners = 0
+
+                for cy, cx in cluster:
+                    # Outer corners
+                    corners += (cy, cx - 1) not in cluster and (
+                        cy - 1,
+                        cx,
+                    ) not in cluster
+                    corners += (cy, cx + 1) not in cluster and (
+                        cy - 1,
+                        cx,
+                    ) not in cluster
+                    corners += (cy, cx - 1) not in cluster and (
+                        cy + 1,
+                        cx,
+                    ) not in cluster
+                    corners += (cy, cx + 1) not in cluster and (
+                        cy + 1,
+                        cx,
+                    ) not in cluster
+                    # Inner corners
+                    corners += (
+                        (cy, cx - 1) in cluster
+                        and (cy - 1, cx) in cluster
+                        and (cy - 1, cx - 1) not in cluster
+                    )
+                    corners += (
+                        (cy, cx + 1) in cluster
+                        and (cy - 1, cx) in cluster
+                        and (cy - 1, cx + 1) not in cluster
+                    )
+                    corners += (
+                        (cy, cx - 1) in cluster
+                        and (cy + 1, cx) in cluster
+                        and (cy + 1, cx - 1) not in cluster
+                    )
+                    corners += (
+                        (cy, cx + 1) in cluster
+                        and (cy + 1, cx) in cluster
+                        and (cy + 1, cx + 1) not in cluster
+                    )
+
+                score += side_length * len(cluster)
+                score2 += corners * len(cluster)
+
+        return (score, score2)

2024/src/aoc/days/day13.py

@@ -0,0 +1,43 @@
+import re
+
+import numpy
+
+from . import CombinedRunner
+
+NASTY_REGEX = r"""Button A: X\+(\d+), Y\+(\d+)
+Button B: X\+(\d+), Y\+(\d+)
+Prize: X=(\d+), Y=(\d+)"""
+
+
+class DayRunner(CombinedRunner):
+    @classmethod
+    def run_both(cls, input: str) -> tuple[int, int]:
+        machines = re.findall(NASTY_REGEX, input)
+
+        cost_to_win = 0
+        cost_to_win2 = 0
+        scale = 10000000000000
+
+        for machine in machines:
+            ax, ay, bx, by, px, py = map(int, machine)
+
+            X = numpy.array([[ax, bx], [ay, by]])
+            B = numpy.array([px, py])
+            B2 = numpy.array([px + scale, py + scale])
+
+            A = numpy.linalg.solve(X, B)
+            A2 = numpy.linalg.solve(X, B2)
+
+            a_press, b_press = map(round, A)
+            a_press2, b_press2 = map(round, A2)
+
+            if a_press * ax + b_press * bx == px and a_press * ay + b_press * by == py:
+                cost_to_win += 3 * a_press + b_press
+
+            if (
+                a_press2 * ax + b_press2 * bx == px + scale
+                and a_press2 * ay + b_press2 * by == py + scale
+            ):
+                cost_to_win2 += 3 * a_press2 + b_press2
+
+        return cost_to_win, cost_to_win2

2024/src/aoc/days/day14.py

@@ -0,0 +1,80 @@
+import itertools
+import math
+import re
+import sys
+
+import numpy
+
+from . import SeparateRunner
+
+NASTY_REGEX = re.compile(r"p=(-?\d+),(-?\d+) v=(-?\d+),(-?\d+)")
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, input: str, width: int = 101, height: int = 103) -> int:
+        points = NASTY_REGEX.findall(input)
+
+        quadrants = [0] * 4
+
+        x_middle = width // 2
+        y_middle = height // 2
+
+        for point in points:
+            x, y, dx, dy = map(int, point)
+
+            rx = ((x + dx * 100) % width + width) % width
+            ry = ((y + dy * 100) % height + height) % height
+
+            match rx:
+                case _ if rx < x_middle:
+                    xq = 0
+                case _ if rx > x_middle:
+                    xq = 1
+                case _:
+                    continue
+
+            match ry:
+                case _ if ry < y_middle:
+                    yq = 0
+                case _ if ry > y_middle:
+                    yq = 1
+                case _:
+                    continue
+
+            quadrants[2 * yq + xq] += 1
+
+        return math.prod(quadrants)
+
+    @classmethod
+    def part2(cls, input: str) -> int:
+        width = 101
+        height = 103
+
+        points = NASTY_REGEX.findall(input)
+        points_fast = numpy.array([list(map(int, point)) for point in points])
+
+        positions = points_fast[:, 0:2]
+        velocities = points_fast[:, 2:]
+
+        target = len(velocities)
+
+        # Assumption: when the easter egg happens, no robots overlap, and this is the
+        # only time this happens. There is no reason this should work but it does.
+        mod_base = numpy.array([width, height])
+        for i in itertools.count(1):
+            positions += velocities
+
+            positions %= mod_base
+            positions += mod_base
+            positions %= mod_base
+
+            if len(numpy.unique(positions, axis=0)) == target:
+                grid = [[" "] * width for _ in range(height)]
+
+                for x, y in positions:
+                    grid[y][x] = "#"
+
+                tree = "\n".join(map((lambda x: "".join(x)), grid))
+                print(tree, file=sys.stderr)
+                return i

2024/src/aoc/days/day15.py

@@ -0,0 +1,161 @@
+import itertools
+
+import numpy
+
+from . import SeparateRunner
+
+
+def parse_input(data: str) -> tuple[numpy.array, str]:
+    grid, steps = data.split("\n\n")
+
+    grid_split = numpy.array([list(line) for line in grid.split("\n")])
+
+    steps = "".join(steps.split("\n"))
+
+    return grid_split, steps
+
+
+def convert_dir(c: str) -> tuple[int, int]:
+    match c:
+        case "^":
+            return 0, -1
+        case ">":
+            return 1, 0
+        case "<":
+            return -1, 0
+        case "v":
+            return 0, 1
+        case other:
+            raise ValueError(f"Invalid movement: {other}")
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, input: str) -> None:
+        grid, steps = parse_input(input)
+
+        y, x = numpy.where(grid == "@")
+        x, y = x[0], y[0]
+
+        for c in steps:
+            dx, dy = convert_dir(c)
+
+            match grid[y + dy, x + dx]:
+                case "#":
+                    continue
+                case "O":
+                    crashed = False
+                    for dist in itertools.count(2):
+                        match grid[y + dist * dy, x + dist * dx]:
+                            case "O":
+                                continue
+                            case "#":
+                                crashed = True
+                                break
+                            case _:
+                                crashed = False
+                                break
+
+                    if crashed:
+                        continue
+
+                    grid[y + dist * dy, x + dist * dx] = "O"
+                case _:
+                    pass
+
+            grid[y, x] = "."
+            x += dx
+            y += dy
+            grid[y, x] = "@"
+
+        stones = numpy.where(grid == "O")
+
+        return sum(100 * y + x for y, x in zip(*stones))
+
+    @classmethod
+    def part2(cls, input: str) -> None:
+        input = input.replace(".", "..")
+        input = input.replace("#", "##")
+        input = input.replace("O", "[]")
+        input = input.replace("@", "@.")
+
+        grid, steps = parse_input(input)
+
+        y, x = numpy.where(grid == "@")
+        x, y = x[0], y[0]
+
+        for c in steps:
+            dx, dy = convert_dir(c)
+
+            match grid[y + dy, x + dx]:
+                case "#":
+                    continue
+                case "]" | "[":
+                    crashed = False
+                    if dy == 0:
+                        # easy case: just move linearly
+                        for dist in itertools.count(2):
+                            match grid[y, x + dist * dx]:
+                                case "[" | "]":
+                                    continue
+                                case "#":
+                                    crashed = True
+                                    break
+                                case _:
+                                    break
+
+                        if crashed:
+                            continue
+
+                        # shuffle all grid points one over
+                        for steps in range(dist, 1, -1):
+                            grid[y, x + dx * steps] = grid[y, x + dx * (steps - 1)]
+                    else:
+                        if grid[y + dy, x] == "[":
+                            to_check = {x, x + 1}
+                        else:
+                            to_check = {x, x - 1}
+
+                        moving_stones = [to_check]
+
+                        for dist in itertools.count(2):
+                            to_check_next = set()
+
+                            for cx in to_check:
+                                match grid[y + dist * dy, cx]:
+                                    case "#":
+                                        crashed = True
+                                        break
+                                    case "[":
+                                        to_check_next.add(cx)
+                                        to_check_next.add(cx + 1)
+                                    case "]":
+                                        to_check_next.add(cx)
+                                        to_check_next.add(cx - 1)
+                                    case _:
+                                        continue
+
+                            if crashed or not to_check_next:
+                                break
+                            moving_stones.append(to_check_next)
+                            to_check = to_check_next
+
+                        if crashed:
+                            continue
+
+                        for steps in range(len(moving_stones), 0, -1):
+                            dist = steps + 1
+                            for cx in moving_stones[steps - 1]:
+                                grid[y + dy * dist, cx] = grid[y + dy * (dist - 1), cx]
+                                grid[y + dy * (dist - 1), cx] = "."
+                case _:
+                    pass
+
+            grid[y, x] = "."
+            x += dx
+            y += dy
+            grid[y, x] = "@"
+
+        stones = numpy.where(grid == "[")
+
+        return sum(100 * y + x for y, x in zip(*stones))

2024/src/aoc/days/day16.py

@@ -0,0 +1,76 @@
+import heapq
+
+import numpy
+
+from . import CombinedRunner
+
+TURNS = (
+    (-1, 1),
+    (1, -1),
+)
+
+
+class DayRunner(CombinedRunner):
+    @classmethod
+    def run_both(cls, input: str) -> tuple[int, int]:
+        grid = numpy.array([list(line) for line in input.strip().split("\n")])
+
+        y, x = numpy.where(grid == "S")
+        x, y = x[0], y[0]
+
+        todo = [(0, x, y, 1, 0)]
+        best = {
+            (x, y, 1, 0): (0, []),
+        }
+
+        def enqueue(dist, x, y, dx, dy, cx, cy, cdx, cdy):
+            if grid[y, x] == "#":
+                return
+
+            if (x, y, dx, dy) not in best or best[x, y, dx, dy][0] > dist:
+                best[x, y, dx, dy] = (dist, [(cx, cy, cdx, cdy)])
+                heapq.heappush(todo, (dist, x, y, dx, dy))
+            elif best[x, y, dx, dy][0] == dist:
+                best[x, y, dx, dy][1].append((cx, cy, cdx, cdy))
+
+        shortest_dist = None
+        finishes = set()
+
+        while todo:
+            dist, x, y, dx, dy = heapq.heappop(todo)
+
+            if best[x, y, dx, dy][0] < dist:
+                continue
+
+            if shortest_dist is not None and shortest_dist < dist:
+                break
+
+            if grid[y, x] == "E":
+                shortest_dist = dist
+                finishes.add((x, y, dx, dy))
+
+            enqueue(dist + 1, x + dx, y + dy, dx, dy, x, y, dx, dy)
+            enqueue(dist + 2001, x - dx, y - dy, dx, dy, x, y, dx, dy)
+
+            for tx, ty in TURNS:
+                ndx = dy * ty
+                ndy = dx * ty
+
+                enqueue(dist + 1001, x + ndx, y + ndy, ndx, ndy, x, y, dx, dy)
+
+        assert shortest_dist is not None, "Should find a path to the exit"
+
+        visited_tiles = {(x, y) for x, y, _, _ in finishes}
+        todo2 = [f for f in finishes]
+        visited_states = set(todo2)
+
+        while todo2:
+            state = todo2.pop()
+
+            for prev in best[state][1]:
+                if prev not in visited_states:
+                    visited_states.add(prev)
+                    visited_tiles.add((prev[0], prev[1]))
+                    todo2.append(prev)
+
+        return shortest_dist, len(visited_tiles)

2024/src/aoc/days/day17.py

@@ -0,0 +1,89 @@
+import re
+
+from . import SeparateRunner
+
+
+def run_program(
+    register_a: int, register_b: int, register_c: int, program: list[int]
+) -> list[int]:
+    ip = 0
+    out = []
+
+    def combo(index: int) -> int:
+        match program[index]:
+            case 0:
+                return 0
+            case 1:
+                return 1
+            case 2:
+                return 2
+            case 3:
+                return 3
+            case 4:
+                return register_a
+            case 5:
+                return register_b
+            case 6:
+                return register_c
+
+    while ip < len(program):
+        match program[ip]:
+            case 0:  # adv
+                register_a = register_a // 2 ** combo(ip + 1)
+            case 1:  # bxl
+                register_b ^= program[ip + 1]
+            case 2:  # bst
+                register_b = combo(ip + 1) & 0x7
+            case 3:  # jnz
+                if register_a != 0:
+                    ip = program[ip + 1]
+                    continue
+            case 4:  # bxc
+                register_b ^= register_c
+            case 5:  # out
+                out.append(combo(ip + 1) & 7)
+            case 6:  # bdv
+                register_b = register_a // 2 ** combo(ip + 1)
+            case 7:  # cdv
+                register_c = register_a // 2 ** combo(ip + 1)
+        ip += 2
+
+    return out
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, input: str) -> str:
+        numbers = re.findall(r"\d+", input)
+
+        register_a, register_b, register_c = map(int, numbers[:3])
+        program = list(map(int, numbers[3:]))
+
+        out = run_program(register_a, register_b, register_c, program)
+
+        return ",".join(map(str, out))
+
+    @classmethod
+    def part2(cls, input: str) -> int:
+        numbers = re.findall(r"\d+", input)
+
+        _, register_b, register_c = map(int, numbers[:3])
+        program = list(map(int, numbers[3:]))
+
+        cur = [0]
+
+        # It came to me in a dream
+        for entry in reversed(program):
+            next_gen = []
+
+            for num in cur:
+                num *= 8
+                for n in range(8):
+                    output = run_program(num + n, register_b, register_c, program)
+                    result = output[0]
+                    if result == entry:
+                        next_gen.append(num + n)
+
+            cur = next_gen
+
+        return cur[0]

2024/src/aoc/days/day18.py

@@ -0,0 +1,70 @@
+from collections import deque
+
+from . import SeparateRunner
+
+
+def parse_input(data: str) -> list[tuple[int, int]]:
+    return [tuple(map(int, line.split(","))) for line in data.strip().split("\n")]
+
+
+def find_exit(fallen: set[tuple[int, int]], width: int, height: int) -> int | None:
+    todo = deque([(0, 0, 0)])
+
+    best = {(0, 0): 0}
+
+    def enqueue(dist: int, x: int, y: int):
+        # print(f"trying {x},{y}")
+        if (x, y) in fallen:
+            return
+
+        if (x, y) not in best or best[x, y] > dist:
+            best[x, y] = dist
+            todo.append((dist, x, y))
+
+    while todo:
+        dist, x, y = todo.popleft()
+        # print(x, y)
+
+        if x == width - 1 and y == height - 1:
+            return dist
+
+        if x > 0:
+            enqueue(dist + 1, x - 1, y)
+
+        if x + 1 < width:
+            enqueue(dist + 1, x + 1, y)
+
+        if y > 0:
+            enqueue(dist + 1, x, y - 1)
+
+        if y + 1 < height:
+            enqueue(dist + 1, x, y + 1)
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(
+        cls, input: str, width: int = 71, height: int = 71, limit: int = 1024
+    ) -> int:
+        falling = parse_input(input)
+
+        return find_exit(set(falling[:limit]), width, height)
+
+    @classmethod
+    def part2(cls, input: str, width: int = 71, height: int = 71) -> str:
+        falling = parse_input(input)
+
+        lower = 0
+        upper = len(falling)
+
+        while lower < upper:
+            mid = lower + (upper - lower) // 2
+
+            if find_exit(set(falling[:mid]), width, height) is not None:
+                lower = mid + 1
+            else:
+                upper = mid
+
+        first_blocker = falling[lower - 1]
+
+        return f"{first_blocker[0]},{first_blocker[1]}"

2024/src/aoc/days/day19.py

@@ -0,0 +1,41 @@
+import collections
+import functools
+
+from . import CombinedRunner
+
+
+def parse_input(data: str) -> tuple[list[str], list[str]]:
+    patterns, designs = data.strip().split("\n\n")
+
+    return patterns.split(", "), designs.split("\n")
+
+
+class DayRunner(CombinedRunner):
+    @classmethod
+    def run_both(cls, input: str) -> int:
+        patterns, designs = parse_input(input)
+
+        by_prefix = collections.defaultdict(list)
+        for prefix in patterns:
+            by_prefix[prefix[0]].append(prefix)
+
+        possible = 0
+        ways = 0
+
+        @functools.cache
+        def is_possible(design: str) -> bool:
+            if not design:
+                return 1
+            else:
+                return sum(
+                    is_possible(design[len(prefix) :])
+                    for prefix in by_prefix[design[0]]
+                    if design.startswith(prefix)
+                )
+
+        for design in designs:
+            if (solve := is_possible(design)) > 0:
+                possible += 1
+                ways += solve
+
+        return possible, ways

2024/src/aoc/days/day20.py

@@ -0,0 +1,82 @@
+import itertools
+
+import numpy
+
+from . import SeparateRunner
+
+DIRECTIONS = [
+    (-1, 0),
+    (1, 0),
+    (0, -1),
+    (0, 1),
+]
+
+CHEATS = [
+    (-2, 0),
+    (2, 0),
+    (0, -2),
+    (0, 2),
+]
+
+
+def parse_path(input: str) -> dict[tuple[int, int], int]:
+    grid = numpy.array(list(map(list, input.strip().split("\n"))))
+
+    ys, xs = numpy.nonzero(grid == "S")
+    sx, sy = int(xs[0]), int(ys[0])
+
+    nx, ny = sx, sy
+
+    path = {
+        (sx, sy): 0,
+    }
+
+    while grid[ny, nx] != "E":
+        x, y = nx, ny
+
+        for dx, dy in DIRECTIONS:
+            if grid[y + dy, x + dx] == "#" or (x + dx, y + dy) in path:
+                continue
+            nx = x + dx
+            ny = y + dy
+            break
+
+        path[nx, ny] = len(path)
+    return path
+
+
+def get_savings(a: tuple[tuple[int, int], int], b: tuple[tuple[int, int], int]) -> int:
+    (ax, ay), ad = a
+    (bx, by), bd = b
+
+    dist = abs(bx - ax) + abs(by - ay)
+    if dist <= 20:
+        return bd - ad - dist
+    else:
+        return 0
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, input: str, limit: int = 100) -> int:
+        path = parse_path(input)
+
+        total = 0
+
+        for (px, py), dist in path.items():
+            for dx, dy in CHEATS:
+                if (other := path.get((px + dx, py + dy))) is not None:
+                    savings = dist - other - 2
+                    if savings >= limit:
+                        total += 1
+
+        return total
+
+    @classmethod
+    def part2(cls, input: str, limit: int = 100) -> int:
+        path = parse_path(input)
+
+        return sum(
+            get_savings(a, b) >= limit
+            for a, b in itertools.combinations(path.items(), 2)
+        )

2024/src/aoc/days/day21.py

@@ -0,0 +1,159 @@
+import functools
+from collections import Counter, defaultdict
+
+from . import SeparateRunner
+
+NUMPAD = {
+    "A": (3, 2),
+    "0": (3, 1),
+    "1": (2, 0),
+    "2": (2, 1),
+    "3": (2, 2),
+    "4": (1, 0),
+    "5": (1, 1),
+    "6": (1, 2),
+    "7": (0, 0),
+    "8": (0, 1),
+    "9": (0, 2),
+}
+
+DIRPAD = {
+    "A": (0, 2),
+    "^": (0, 1),
+    "<": (1, 0),
+    "v": (1, 1),
+    ">": (1, 2),
+}
+
+
+@functools.cache
+def shortest_numpad(from_: str, to: str) -> list[str]:
+    inverse = set(NUMPAD.values())
+    ay, ax = NUMPAD[from_]
+    by, bx = NUMPAD[to]
+
+    dx, dy = bx - ax, by - ay
+
+    sx = "<" if dx < 0 else ">"
+    sy = "^" if dy < 0 else "v"
+
+    if dx > 0 and (by, ax) in inverse or (ay, bx) not in inverse:
+        return abs(dy) * sy + abs(dx) * sx + "A"
+    else:
+        return abs(dx) * sx + abs(dy) * sy + "A"
+
+
+@functools.cache
+def shortest_dirpad(from_: str, to: str) -> str:
+    inverse = set(DIRPAD.values())
+    ay, ax = DIRPAD[from_]
+    by, bx = DIRPAD[to]
+
+    dx, dy = bx - ax, by - ay
+    sx = "<" if dx < 0 else ">"
+    sy = "^" if dy < 0 else "v"
+
+    if dx > 0 and (by, ax) in inverse or (ay, bx) not in inverse:
+        return abs(dy) * sy + abs(dx) * sx + "A"
+    else:
+        return abs(dx) * sx + abs(dy) * sy + "A"
+
+
+def encode_shortest_numpad(code: str) -> str:
+    pos = "A"
+
+    res = ""
+
+    for c in code:
+        res += shortest_numpad(pos, c)
+        # print(c, res)
+        pos = c
+
+    return res
+
+
+def encode_shortest_dirpad(code: str) -> str:
+    pos = "A"
+
+    res = ""
+
+    for c in code:
+        if pos != c:
+            res += shortest_dirpad(pos, c)
+        else:
+            res += "A"
+        pos = c
+
+    return res
+
+
+def decode(code: str, pad: dict[str, tuple[int, int]]) -> str:
+    result = ""
+    inverse = {v: k for k, v in pad.items()}
+
+    y, x = pad["A"]
+
+    for i, c in enumerate(code):
+        match c:
+            case "A":
+                result += inverse[y, x]
+            case "^":
+                y -= 1
+            case "v":
+                y += 1
+            case "<":
+                x -= 1
+            case ">":
+                x += 1
+
+        if (y, x) not in inverse:
+            raise ValueError(
+                f"""Moved off the board {x, y}, after processing {c}.
+                Path so far: {result} (from {code[:i]})"""
+            )
+
+    return result
+
+
+def count_steps(path: str, count: int) -> dict[str, int]:
+    cur = "A"
+    counts = defaultdict(int)
+
+    for c in path:
+        step = shortest_dirpad(cur, c)
+        cur = c
+        counts[step] += count
+
+    return counts
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, input: str) -> int:
+        result = 0
+        for code in input.strip().split("\n"):
+            numpad = encode_shortest_numpad(code)
+            robot1 = encode_shortest_dirpad(numpad)
+            robot2 = encode_shortest_dirpad(robot1)
+
+            result += int(code[:-1]) * len(robot2)
+
+        return result
+
+    @classmethod
+    def part2(cls, input: str, robots=25) -> int:
+        result = 0
+        for code in input.strip().split("\n"):
+            numpad = encode_shortest_numpad(code)
+            keypresses = Counter([numpad])
+
+            for _ in range(robots + 1):
+                new_presses = Counter()
+                for subroute, count in keypresses.items():
+                    new_presses.update(count_steps(subroute, count))
+
+                keypresses = new_presses
+
+            result += int(code[:-1]) * keypresses.total()
+
+        return result

2024/src/aoc/days/day22.py

@@ -0,0 +1,41 @@
+from collections import defaultdict
+
+import numpy
+from numpy.lib.stride_tricks import sliding_window_view
+
+from . import CombinedRunner
+
+
+def advance(secrets: numpy.array) -> numpy.array:
+    new_secrets = (secrets ^ (secrets << 6)) & 0xFFFFFF
+    new_secrets ^= new_secrets >> 5
+    new_secrets ^= new_secrets << 11
+    new_secrets &= 0xFFFFFF
+
+    return new_secrets
+
+
+class DayRunner(CombinedRunner):
+    @classmethod
+    def run_both(cls, input: str) -> tuple[int, int]:
+        secrets = numpy.fromstring(input, dtype=int, sep="\n")
+
+        progression = [secrets]
+
+        for _ in range(2000):
+            secrets = advance(secrets)
+            progression.append(secrets)
+
+        field = numpy.stack(progression, axis=-1) % 10
+        delta = field[:, 1:] - field[:, :-1]
+        windows = sliding_window_view(delta, 4, axis=1)
+
+        per_signal = defaultdict(int)
+
+        for row_scores, row_deltas in zip(field, windows):
+            unique, positions = numpy.unique(row_deltas, return_index=True, axis=0)
+
+            for key, bananas in zip(unique, row_scores[positions + 4]):
+                per_signal[tuple(key)] += bananas
+
+        return secrets.sum(), max(per_signal.values())

2024/src/aoc/days/day23.py

@@ -0,0 +1,42 @@
+from collections import defaultdict
+
+import networkx
+
+from . import SeparateRunner
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, input: str) -> int:
+        edges = defaultdict(set)
+
+        for line in input.strip().split("\n"):
+            a, b = line.split("-")
+            edges[a].add(b)
+            edges[b].add(a)
+
+        found = set()
+
+        for a, out in edges.items():
+            if a[0] != "t":
+                continue
+
+            for b in out:
+                for c in edges[b]:
+                    if c in out:
+                        found.add(tuple(sorted([a, b, c])))
+
+        return len(found)
+
+    @classmethod
+    def part2(cls, input: str) -> str:
+        graph = networkx.Graph()
+
+        for line in input.strip().split("\n"):
+            a, b = line.split("-")
+            graph.add_edge(a, b)
+
+        cliques = networkx.find_cliques(graph)
+        max_clique = max(cliques, key=len)
+
+        return ",".join(sorted(max_clique))

2024/src/aoc/days/day24.py

@@ -0,0 +1,133 @@
+import functools
+import re
+
+from . import SeparateRunner
+
+
+def parse_input(input: str) -> tuple[dict[str, int], dict[str, tuple[str, str, str]]]:
+    variable_part, rules_part = input.strip().split("\n\n")
+
+    variables = {}
+
+    for line in variable_part.splitlines():
+        variable, value = line.split(": ")
+        variables[variable] = int(value)
+
+    rules = {}
+
+    for first, op, second, result in re.findall(
+        r"(\w+) (XOR|OR|AND) (\w+) -> (\w+)", rules_part
+    ):
+        rules[result] = (first, op, second)
+
+    return variables, rules
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, input: str) -> int:
+        variables, rules = parse_input(input)
+
+        @functools.cache
+        def get_value(variable: str) -> int:
+            if variable in variables:
+                return variables[variable]
+
+            first, op, second = rules[variable]
+            first_v = get_value(first)
+            second_v = get_value(second)
+
+            match op:
+                case "AND":
+                    return first_v & second_v
+                case "OR":
+                    return first_v | second_v
+                case "XOR":
+                    return first_v ^ second_v
+
+        result = 0
+        for variable in reversed(sorted(rules)):
+            if not variable.startswith("z"):
+                continue
+            result = result * 2 + get_value(variable)
+
+        return result
+
+    @classmethod
+    def part2(cls, input: str) -> str:
+        variables, rules = parse_input(input)
+
+        max_bit = int(
+            max(variable for variable in rules if variable.startswith("z"))[1:]
+        )
+
+        def find_invalid(output: str, pattern) -> set[str]:
+            if pattern is None:
+                return set()
+
+            if output in rules:
+                left, op, right = rules[output]
+            elif output == pattern:
+                return set()
+            else:
+                return {output}
+
+            pop, pleft, pright = pattern
+
+            if op != pop:
+                return {output}
+
+            wrong_normal = find_invalid(left, pleft) | find_invalid(right, pright)
+            wrong_mirror = find_invalid(left, pright) | find_invalid(right, pleft)
+
+            least_wrong = min(wrong_mirror, wrong_normal, key=len)
+
+            return least_wrong
+
+        assert max_bit >= 3
+
+        # First one is a half adder, that's a simple pattern
+        invalid = find_invalid("z00", ["XOR", "x00", "y00"])
+        # Second one is missing a reference to the before-previous adder, so it's a
+        # slightly different patterns
+        invalid |= find_invalid(
+            "z01", ["XOR", ["AND", "x00", "y00"], ["XOR", "x01", "y01"]]
+        )
+        # Needed a second lookback to determine that `ktp` is valid
+        invalid |= find_invalid(
+            "z02",
+            [
+                "XOR",
+                ["XOR", "x02", "y02"],
+                [
+                    "OR",
+                    ["AND", "x01", "y01"],
+                    ["AND", ["XOR", "x01", "y01"], ["AND", "x00", "y00"]],
+                ],
+            ],
+        )
+
+        for n in range(3, max_bit):
+            xcurr = f"x{n:02}"
+            ycurr = f"y{n:02}"
+            zcurr = f"z{n:02}"
+            xprev = f"x{n-1:02}"
+            yprev = f"y{n-1:02}"
+
+            invalid |= find_invalid(
+                zcurr,
+                [
+                    "XOR",
+                    ["XOR", xcurr, ycurr],
+                    [
+                        "OR",
+                        ["AND", xprev, yprev],
+                        ["AND", ["XOR", xprev, yprev], ["OR", None, None]],
+                    ],
+                ],
+            )
+
+        # This code somehow believes `ktp` is invalid, but it's fine on closer
+        # inspection. Will figure that out later.
+
+        return ",".join(sorted(invalid))

2024/src/aoc/days/day25.py

@@ -0,0 +1,29 @@
+import numpy
+
+from . import CombinedRunner
+
+
+class DayRunner(CombinedRunner):
+    @classmethod
+    def run_both(cls, input: str) -> tuple[int, None]:
+        blocks = input.strip().split("\n\n")
+
+        keys = []
+        locks = []
+
+        for block in blocks:
+            grid = numpy.array(list(map(list, block.splitlines())))
+            heights = numpy.count_nonzero(grid == "#", axis=0)
+
+            if block.startswith("#####"):
+                locks.append(heights)
+            else:
+                keys.append(heights)
+
+        locks = numpy.stack(locks, axis=0)
+
+        fitting = sum(
+            numpy.count_nonzero(numpy.all((key + locks) <= 7, axis=1)) for key in keys
+        )
+
+        return fitting, None

2024/tests/samples/12.1.txt

@@ -0,0 +1,4 @@
+AAAA
+BBCD
+BBCC
+EEEC

2024/tests/samples/12.2.txt

@@ -0,0 +1,5 @@
+OOOOO
+OXOXO
+OOOOO
+OXOXO
+OOOOO

2024/tests/samples/12.3.txt

@@ -0,0 +1,10 @@
+RRRRIICCFF
+RRRRIICCCF
+VVRRRCCFFF
+VVRCCCJFFF
+VVVVCJJCFE
+VVIVCCJJEE
+VVIIICJJEE
+MIIIIIJJEE
+MIIISIJEEE
+MMMISSJEEE

2024/tests/samples/13.txt

@@ -0,0 +1,15 @@
+Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279

2024/tests/samples/14.txt

@@ -0,0 +1,12 @@
+p=0,4 v=3,-3
+p=6,3 v=-1,-3
+p=10,3 v=-1,2
+p=2,0 v=2,-1
+p=0,0 v=1,3
+p=3,0 v=-2,-2
+p=7,6 v=-1,-3
+p=3,0 v=-1,-2
+p=9,3 v=2,3
+p=7,3 v=-1,2
+p=2,4 v=2,-3
+p=9,5 v=-3,-3

2024/tests/samples/15.1.txt

@@ -0,0 +1,21 @@
+##########
+#..O..O.O#
+#......O.#
+#.OO..O.O#
+#..O@..O.#
+#O#..O...#
+#O..O..O.#
+#.OO.O.OO#
+#....O...#
+##########
+
+<vv>^<v^>v>^vv^v>v<>v^v<v<^vv<<<^><<><>>v<vvv<>^v^>^<<<><<v<<<v^vv^v>^
+vvv<<^>^v^^><<>>><>^<<><^vv^^<>vvv<>><^^v>^>vv<>v<<<<v<^v>^<^^>>>^<v<v
+><>vv>v^v^<>><>>>><^^>vv>v<^^^>>v^v^<^^>v^^>v^<^v>v<>>v^v^<v>v^^<^^vv<
+<<v<^>>^^^^>>>v^<>vvv^><v<<<>^^^vv^<vvv>^>v<^^^^v<>^>vvvv><>>v^<<^^^^^
+^><^><>>><>^^<<^^v>>><^<v>^<vv>>v>>>^v><>^v><<<<v>>v<v<v>vvv>^<><<>^><
+^>><>^v<><^vvv<^^<><v<<<<<><^v<<<><<<^^<v<^^^><^>>^<v^><<<^>>^v<v^v<v^
+>^>>^v>vv>^<<^v<>><<><<v<<v><>v<^vv<<<>^^v^>^^>>><<^v>>v^v><^^>>^<>vv^
+<><^^>^^^<><vvvvv^v<v<<>^v<v>v<<^><<><<><<<^^<<<^<<>><<><^^^>^^<>^>v<>
+^^>vv<^v^v<vv>^<><v<^v>^^^>>>^^vvv^>vvv<>>>^<^>>>>>^<<^v>^vvv<>^<><<v>
+v^^>>><<^^<>>^v^<v^vv<>v^<<>^<^v^v><^<<<><<^<v><v<>vv>>v><v^<vv<>v^<<^

2024/tests/samples/15.2.txt

@@ -0,0 +1,10 @@
+########
+#..O.O.#
+##@.O..#
+#...O..#
+#.#.O..#
+#...O..#
+#......#
+########
+
+<^^>>>vv<v>>v<<

2024/tests/samples/15.3.txt

@@ -0,0 +1,9 @@
+#######
+#...#.#
+#.....#
+#..OO@#
+#..O..#
+#.....#
+#######
+
+<vv<<^^<<^^

2024/tests/samples/16.1.txt

@@ -0,0 +1,15 @@
+###############
+#.......#....E#
+#.#.###.#.###.#
+#.....#.#...#.#
+#.###.#####.#.#
+#.#.#.......#.#
+#.#.#####.###.#
+#...........#.#
+###.#.#####.#.#
+#...#.....#.#.#
+#.#.#.###.#.#.#
+#.....#...#.#.#
+#.###.#.#.#.#.#
+#S..#.....#...#
+###############

2024/tests/samples/16.2.txt

@@ -0,0 +1,17 @@
+#################
+#...#...#...#..E#
+#.#.#.#.#.#.#.#.#
+#.#.#.#...#...#.#
+#.#.#.#.###.#.#.#
+#...#.#.#.....#.#
+#.#.#.#.#.#####.#
+#.#...#.#.#.....#
+#.#.#####.#.###.#
+#.#.#.......#...#
+#.#.###.#####.###
+#.#.#...#.....#.#
+#.#.#.#####.###.#
+#.#.#.........#.#
+#.#.#.#########.#
+#S#.............#
+#################

2024/tests/samples/17.1.txt

@@ -0,0 +1,5 @@
+Register A: 729
+Register B: 0
+Register C: 0
+
+Program: 0,1,5,4,3,0

2024/tests/samples/17.2.txt

@@ -0,0 +1,5 @@
+Register A: 2024
+Register B: 0
+Register C: 0
+
+Program: 0,3,5,4,3,0

2024/tests/samples/18.txt

@@ -0,0 +1,25 @@
+5,4
+4,2
+4,5
+3,0
+2,1
+6,3
+2,4
+1,5
+0,6
+3,3
+2,6
+5,1
+1,2
+5,5
+2,5
+6,5
+1,4
+0,4
+6,4
+1,1
+6,1
+1,0
+0,5
+1,6
+2,0

2024/tests/samples/19.txt

@@ -0,0 +1,10 @@
+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb

2024/tests/samples/20.txt

@@ -0,0 +1,15 @@
+###############
+#...#...#.....#
+#.#.#.#.#.###.#
+#S#...#.#.#...#
+#######.#.#.###
+#######.#.#...#
+#######.#.###.#
+###..E#...#...#
+###.#######.###
+#...###...#...#
+#.#####.#.###.#
+#.#...#.#.#...#
+#.#.#.#.#.#.###
+#...#...#...###
+###############

2024/tests/samples/21.txt

@@ -0,0 +1,5 @@
+029A
+980A
+179A
+456A
+379A

2024/tests/samples/22.1.txt

@@ -0,0 +1,4 @@
+1
+10
+100
+2024

2024/tests/samples/22.2.txt

@@ -0,0 +1,4 @@
+1
+2
+3
+2024

2024/tests/samples/23.txt

@@ -0,0 +1,32 @@
+kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn

2024/tests/samples/24.txt

@@ -0,0 +1,47 @@
+x00: 1
+x01: 0
+x02: 1
+x03: 1
+x04: 0
+y00: 1
+y01: 1
+y02: 1
+y03: 1
+y04: 1
+
+ntg XOR fgs -> mjb
+y02 OR x01 -> tnw
+kwq OR kpj -> z05
+x00 OR x03 -> fst
+tgd XOR rvg -> z01
+vdt OR tnw -> bfw
+bfw AND frj -> z10
+ffh OR nrd -> bqk
+y00 AND y03 -> djm
+y03 OR y00 -> psh
+bqk OR frj -> z08
+tnw OR fst -> frj
+gnj AND tgd -> z11
+bfw XOR mjb -> z00
+x03 OR x00 -> vdt
+gnj AND wpb -> z02
+x04 AND y00 -> kjc
+djm OR pbm -> qhw
+nrd AND vdt -> hwm
+kjc AND fst -> rvg
+y04 OR y02 -> fgs
+y01 AND x02 -> pbm
+ntg OR kjc -> kwq
+psh XOR fgs -> tgd
+qhw XOR tgd -> z09
+pbm OR djm -> kpj
+x03 XOR y03 -> ffh
+x00 XOR y04 -> ntg
+bfw OR bqk -> z06
+nrd XOR fgs -> wpb
+frj XOR qhw -> z04
+bqk OR frj -> z07
+y03 OR x01 -> nrd
+hwm AND bqk -> z03
+tgd XOR rvg -> z12
+tnw OR pbm -> gnj

2024/tests/samples/25.txt

@@ -0,0 +1,39 @@
+#####
+.####
+.####
+.####
+.#.#.
+.#...
+.....
+
+#####
+##.##
+.#.##
+...##
+...#.
+...#.
+.....
+
+.....
+#....
+#....
+#...#
+#.#.#
+#.###
+#####
+
+.....
+.....
+#.#..
+###..
+###.#
+###.#
+#####
+
+.....
+.....
+.....
+#....
+#.#..
+#.#.#
+#####

2024/tests/test_day12.py

@@ -0,0 +1,21 @@
+import pytest
+
+from aoc.days.day12 import DayRunner
+
+from . import get_data
+
+
+@pytest.mark.parametrize(
+    "data,result",
+    [(get_data(12, 1), 140), (get_data(12, 2), 772), (get_data(12, 3), 1930)],
+)
+def test_sample_part1(data: str, result: int) -> None:
+    assert DayRunner.part1(data) == result
+
+
+@pytest.mark.parametrize(
+    "data,result",
+    [(get_data(12, 1), 80), (get_data(12, 2), 436), (get_data(12, 3), 1206)],
+)
+def test_sample_part2(data: str, result: int) -> None:
+    assert DayRunner.part2(data) == result

2024/tests/test_day13.py

@@ -0,0 +1,7 @@
+from aoc.days.day13 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(13)) == 480

2024/tests/test_day14.py

@@ -0,0 +1,7 @@
+from aoc.days.day14 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(14), width=11, height=7) == 12

2024/tests/test_day15.py

@@ -0,0 +1,27 @@
+import pytest
+
+from aoc.days.day15 import DayRunner
+
+from . import get_data
+
+
+@pytest.mark.parametrize(
+    "data,result",
+    [
+        (get_data(15, 1), 10092),
+        (get_data(15, 2), 2028),
+    ],
+)
+def test_sample_part1(data: str, result: int) -> None:
+    assert DayRunner.part1(data) == result
+
+
+@pytest.mark.parametrize(
+    "data,result",
+    [
+        (get_data(15, 1), 9021),
+        (get_data(15, 3), 618),
+    ],
+)
+def test_sample_part2(data: str, result: int) -> None:
+    assert DayRunner.part2(data) == result

2024/tests/test_day16.py

@@ -0,0 +1,27 @@
+import pytest
+
+from aoc.days.day16 import DayRunner
+
+from . import get_data
+
+
+@pytest.mark.parametrize(
+    "data,result",
+    [
+        (get_data(16, 1), 7036),
+        (get_data(16, 2), 11048),
+    ],
+)
+def test_sample_part1(data: str, result: int) -> None:
+    assert DayRunner.part1(data) == result
+
+
+@pytest.mark.parametrize(
+    "data,result",
+    [
+        (get_data(16, 1), 45),
+        (get_data(16, 2), 64),
+    ],
+)
+def test_sample_part2(data: str, result: int) -> None:
+    assert DayRunner.part2(data) == result

2024/tests/test_day17.py

@@ -0,0 +1,11 @@
+from aoc.days.day17 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(17, 1)) == "4,6,3,5,6,3,5,2,1,0"
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(17, 2)) == 117440

2024/tests/test_day18.py

@@ -0,0 +1,11 @@
+from aoc.days.day18 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(18), width=7, height=7, limit=12) == 22
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(18), width=7, height=7) == "6,1"

2024/tests/test_day19.py

@@ -0,0 +1,11 @@
+from aoc.days.day19 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(19)) == 6
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(19)) == 16

2024/tests/test_day20.py

@@ -0,0 +1,11 @@
+from aoc.days.day20 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(20), limit=1) == 44
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(20), limit=50) == 285

2024/tests/test_day21.py

@@ -0,0 +1,55 @@
+import pytest
+
+from aoc.days.day21 import (
+    DayRunner,
+    encode_shortest_dirpad,
+    encode_shortest_numpad,
+)
+
+from . import get_data
+
+
+def test_encode_shortest_numpad() -> None:
+    assert encode_shortest_numpad("029A") in (
+        "<A^A>^^AvvvA",
+        "<A^A^>^AvvvA",
+        "<A^A^^>AvvvA",
+    )
+
+
+def test_encode_shortest_dirpad() -> None:
+    numpad_encoded = encode_shortest_numpad("029A")
+    assert len(encode_shortest_dirpad(numpad_encoded)) == len(
+        "v<<A>>^A<A>AvA<^AA>A<vAAA>^A"
+    )
+
+
+@pytest.mark.parametrize(
+    "code,answer",
+    [
+        (
+            "029A",
+            "<vA<AA>>^AvAA<^A>A<v<A>>^AvA^A<vA>^A<v<A>^A>AAvA^A<v<A>A>^AAAvA<^A>A",
+        ),
+        ("980A", "<v<A>>^AAAvA^A<vA<AA>>^AvAA<^A>A<v<A>A>^AAAvA<^A>A<vA>^A<A>A"),
+        (
+            "179A",
+            "<v<A>>^A<vA<A>>^AAvAA<^A>A<v<A>>^AAvA^A<vA>^AA<A>A<v<A>A>^AAAvA<^A>A",
+        ),
+        ("456A", "<v<A>>^AA<vA<A>>^AAvAA<^A>A<vA>^A<A>A<vA>^A<A>A<v<A>A>^AAvA<^A>A"),
+        ("379A", "<v<A>>^AvA^A<vA<AA>>^AAvA<^A>AAvA^A<vA>^AA<A>A<v<A>A>^AAAvA<^A>A"),
+    ],
+)
+def test_encode_shortest_dirpad_twice(code: str, answer: str) -> None:
+    numpad_encoded = encode_shortest_numpad(code)
+    robot1 = encode_shortest_dirpad(numpad_encoded)
+    robot2 = encode_shortest_dirpad(robot1)
+    assert len(robot2) == len(answer)
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(21)) == 126384
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(21), robots=2) == 126384

2024/tests/test_day22.py

@@ -0,0 +1,11 @@
+from aoc.days.day22 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(22, 1)) == 37327623
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(22, 2)) == 23

2024/tests/test_day23.py

@@ -0,0 +1,11 @@
+from aoc.days.day23 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(23)) == 7
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(get_data(23)) == "co,de,ka,ta"

2024/tests/test_day24.py

@@ -0,0 +1,7 @@
+from aoc.days.day24 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(24)) == 2024

2024/tests/test_day25.py

@@ -0,0 +1,7 @@
+from aoc.days.day25 import DayRunner
+
+from . import get_data
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(get_data(25)) == 3

2024/uv.lock

@@ -7,6 +7,7 @@ version = "0.1.0"
 source = { editable = "." }
 dependencies = [
     { name = "click" },
+    { name = "networkx" },
     { name = "numpy" },
 ]
 
@@ -20,6 +21,7 @@ dev = [
 [package.metadata]
 requires-dist = [
     { name = "click", specifier = ">=8.1.7" },
+    { name = "networkx", specifier = ">=3.4.2" },
     { name = "numpy", specifier = ">=2.1.2" },
 ]
 
@@ -35,7 +37,7 @@ name = "click"
 version = "8.1.7"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
-    { name = "colorama", marker = "platform_system == 'Windows'" },
+    { name = "colorama", marker = "sys_platform == 'win32'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/96/d3/f04c7bfcf5c1862a2a5b845c6b2b360488cf47af55dfa79c98f6a6bf98b5/click-8.1.7.tar.gz", hash = "sha256:ca9853ad459e787e2192211578cc907e7594e294c7ccc834310722b41b9ca6de", size = 336121 }
 wheels = [
@@ -92,6 +94,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/2a/e2/5d3f6ada4297caebe1a2add3b126fe800c96f56dbe5d1988a2cbe0b267aa/mypy_extensions-1.0.0-py3-none-any.whl", hash = "sha256:4392f6c0eb8a5668a69e23d168ffa70f0be9ccfd32b5cc2d26a34ae5b844552d", size = 4695 },
 ]
 
+[[package]]
+name = "networkx"
+version = "3.4.2"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/fd/1d/06475e1cd5264c0b870ea2cc6fdb3e37177c1e565c43f56ff17a10e3937f/networkx-3.4.2.tar.gz", hash = "sha256:307c3669428c5362aab27c8a1260aa8f47c4e91d3891f48be0141738d8d053e1", size = 2151368 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/b9/54/dd730b32ea14ea797530a4479b2ed46a6fb250f682a9cfb997e968bf0261/networkx-3.4.2-py3-none-any.whl", hash = "sha256:df5d4365b724cf81b8c6a7312509d0c22386097011ad1abe274afd5e9d3bbc5f", size = 1723263 },
+]
+
 [[package]]
 name = "numpy"
 version = "2.1.2"

2025/README.md

@@ -0,0 +1,5 @@
+# Advent of Code 2025
+
+New year, new challenge. With the shorter year, I'm going to try to use a different language every
+day, restricting myself to programming languages my employer uses in production. Let's call it the
+**Full Stack Challenge**.

2025/day01/README.md

@@ -0,0 +1,17 @@
+# Day 01: Nix
+
+Nix is a functional language made for the Nix package manager. As 
+
+To run the solution program, start the `nix` repl with the solution program and call the `solve`
+function with the path to the input file.
+
+```console
+$ nix repl --option max-call-depth 10000 --file solve.nix
+nix-repl> solve ./sample.txt
+```
+
+Some observations:
+
+- The `max-call-depth` needs to be bumped to at least 10k for the main input files, otherwise you
+  hit the limit in the recursion.
+- The standard library is lacking several basics but most of those you can build yourself

2025/day01/sample.txt

@@ -0,0 +1,10 @@
+L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82

2025/day01/solve.nix

@@ -0,0 +1,37 @@
+{
+    solve = input_file:
+        let
+            data = builtins.readFile input_file;
+            lines = builtins.filter (s: s != "" && builtins.isString s) (builtins.split "\n" data);
+
+            # Basic maths because the standard library doesn't have it
+            mod = a: b: a - (a / b) * b;
+            abs = n: if n < 0 then -n else n;
+
+            recurse = list: position: score1: score2:
+                let
+                    first = builtins.head list;
+                    # This is not guaranteed to work but it's good enough
+                    num_part = builtins.substring 1 999 first;
+                    num = builtins.fromJSON num_part;
+                    delta = mod (if (builtins.substring 0 1 first) == "R" then num else -num) 100;
+                    next = mod (position + delta + 100) 100;
+                    
+                    score = if next == 0 then 1 else 0;
+                    circles = num / 100;
+
+                    passed = if position == 0 then
+                        0
+                    else
+                        if delta < 0 && delta + position <= 0 || delta > 0 && delta + position >= 100 then
+                            1
+                        else
+                            0;
+                in
+                    if list == [] then
+                        [score1 score2]
+                    else
+                        recurse (builtins.tail list) next (score + score1) (score2 + passed + circles);
+        in
+            recurse lines 50 0 0;
+}

2025/day02/README.md

@@ -0,0 +1,29 @@
+# Day 02: Terraform
+
+The code assumes an input file at `../inputs/02.txt`. Other than that, simply try to run as follows:
+
+```console
+$ terraform init
+…
+Initializing the backend...
+Initializing modules...
+Initializing provider plugins...
+
+Terraform has been successfully initialized!
+
+You may now begin working with Terraform. Try running "terraform plan" to see
+any changes that are required for your infrastructure. All Terraform commands
+should now work.
+
+If you ever set or change modules or backend configuration for Terraform,
+rerun this command to reinitialize your working directory. If you forget, other
+commands will detect it and remind you to do so if necessary.
+$ terraform plan
+….
+
+Changes to Outputs:
+  + part1 = secret
+  + part2 = also secret
+
+You can apply this plan to save these new output values to the Terraform state, without changing any real infrastructure.
+```

2025/day02/main.tf

@@ -0,0 +1,29 @@
+locals {
+  input   = file("../inputs/02.txt")
+  ranges  = split(",", chomp(local.input))
+  min_max = [for r in local.ranges : split("-", r)]
+}
+
+module "check_range" {
+  source = "./range"
+  count  = length(local.min_max)
+
+  min = local.min_max[count.index][0]
+  max = local.min_max[count.index][1]
+}
+
+module "check_range2" {
+  source = "./range2"
+  count  = length(local.min_max)
+
+  min = local.min_max[count.index][0]
+  max = local.min_max[count.index][1]
+}
+
+output "part1" {
+  value = sum(module.check_range[*].invalid_sum)
+}
+
+output "part2" {
+  value = sum(module.check_range2[*].invalid_sum)
+}

2025/day02/range/item/main.tf

@@ -0,0 +1,15 @@
+variable "part" {
+  type = number
+}
+
+variable "repetitions" {
+  type = number
+}
+
+locals {
+  repeated = [for _ in range(var.repetitions) : tostring(var.part)]
+}
+
+output "full" {
+  value = join("", local.repeated)
+}

2025/day02/range/main.tf

@@ -0,0 +1,46 @@
+variable "min" {
+  type = number
+}
+
+variable "max" {
+  type = number
+}
+
+variable "repetitions" {
+  type    = number
+  default = 2
+}
+
+locals {
+  digits       = floor(length(tostring(var.max)) / var.repetitions)
+  maximum      = substr(tostring(var.max), 0, local.digits)
+  real_maximum = length(tostring(var.max)) % var.repetitions == 0 ? tonumber(local.maximum) : pow(10, local.digits)
+
+  minimum_prefix = substr(tostring(var.min), 0, length(tostring(var.min)) - local.digits * (var.repetitions - 1))
+  minimum        = local.minimum_prefix == "" ? 1 : tonumber(local.minimum_prefix)
+
+  count = max(local.real_maximum - local.minimum + 1, 1)
+
+  can_work = anytrue([for n in range(length(tostring(var.min)), length(tostring(var.max)) + 1) : n % var.repetitions == 0])
+}
+
+// This "candidates" module ought really be a list comprehension from range, but Terraform does not
+// allow you to create ranges longer than 1024.
+module "candidates" {
+  source      = "./item"
+  count       = local.can_work ? local.count : 0
+  part        = count.index + local.minimum
+  repetitions = var.repetitions
+}
+
+locals {
+  invalid = [for n in module.candidates[*].full : n if n >= var.min && n <= var.max]
+}
+
+output "invalid_sum" {
+  value = length(local.invalid) > 0 ? sum(local.invalid) : 0
+}
+
+output "invalid" {
+  value = toset(local.invalid)
+}

2025/day02/range2/main.tf

@@ -0,0 +1,27 @@
+variable "min" {
+  type = number
+}
+
+variable "max" {
+  type = number
+}
+
+locals {
+  digits = length(tostring(var.max))
+}
+
+module "range" {
+  source      = "../range"
+  count       = local.digits - 1
+  max         = var.max
+  min         = var.min
+  repetitions = count.index + 2
+}
+
+locals {
+  results = setunion(module.range[*].invalid...)
+}
+
+output "invalid_sum" {
+  value = length(local.results) > 0 ? sum(local.results) : 0
+}

2025/day02/tests.tftest.hcl

@@ -0,0 +1,128 @@
+run "sample-1-1" {
+  module {
+    source = "./range"
+  }
+
+  variables {
+    min = 11
+    max = 22
+  }
+
+  assert {
+    condition     = output.invalid_sum == 33
+    error_message = "Incorrect result"
+  }
+}
+
+run "sample-1-2" {
+  module {
+    source = "./range"
+  }
+
+  variables {
+    min = 95
+    max = 115
+  }
+
+  assert {
+    condition     = output.invalid_sum == 99
+    error_message = "Incorrect result"
+  }
+}
+
+run "sample-2-1" {
+  module {
+    source = "./range2"
+  }
+
+  variables {
+    min = 11
+    max = 22
+  }
+
+  assert {
+    condition     = output.invalid_sum == 33
+    error_message = "Incorrect result"
+  }
+}
+
+run "sample-2-2" {
+  module {
+    source = "./range2"
+  }
+
+  variables {
+    min = 95
+    max = 115
+  }
+
+  assert {
+    condition     = output.invalid_sum == 210
+    error_message = "Incorrect result"
+  }
+}
+
+run "sample-2-3" {
+  module {
+    source = "./range2"
+  }
+
+  variables {
+    min = 998
+    max = 1012
+  }
+
+  assert {
+    condition     = output.invalid_sum == 2009
+    error_message = "Incorrect result"
+  }
+}
+
+run "sample-2-2-detail" {
+  module {
+    source = "./range"
+  }
+
+  variables {
+    min         = 95
+    max         = 115
+    repetitions = 3
+  }
+
+  assert {
+    condition     = output.invalid_sum == 111
+    error_message = "Incorrect result"
+  }
+}
+
+run "sample-2-10" {
+  module {
+    source = "./range2"
+  }
+
+  variables {
+    min = 824824821
+    max = 824824827
+  }
+
+  assert {
+    condition     = output.invalid_sum == 824824824
+    error_message = "Incorrect result"
+  }
+}
+
+run "sample-2-11" {
+  module {
+    source = "./range2"
+  }
+
+  variables {
+    min = 2121212118
+    max = 2121212124
+  }
+
+  assert {
+    condition     = output.invalid_sum == 2121212121
+    error_message = "Incorrect result"
+  }
+}

2025/day03/README.md

@@ -0,0 +1,4 @@
+# Day 03: Bash
+
+Simple as can be, simply run `./solve.sh <input file>` and get both answers. While I allowed myself
+to use `coreutils` with bash, they turned out to be entirely unnecessary. Pure bash just works.

2025/day03/sample.txt

@@ -0,0 +1,4 @@
+987654321111111
+811111111111119
+234234234234278
+818181911112111

2025/day03/solve.sh

@@ -0,0 +1,64 @@
+#!/bin/bash
+
+if [[ $# -lt 1 ]]; then
+    echo "Usage: $0 <input file>" >&2
+    exit 1
+fi
+
+joltage() {
+    local first second c i
+
+    first=0
+    second=0
+
+    for ((i = 0; i < ${#1}; i++)); do
+        c="${1:$i:1}"
+
+        if [[ $second -gt $first ]]; then
+            first="$second"
+            second="$c"
+        elif [[ $c -gt $second ]]; then
+            second="$c"
+        fi
+    done
+
+    echo "$first$second"
+}
+
+joltage2() {
+    local c i d e n digits
+
+    digits=(0 0 0 0 0 0 0 0 0 0 0 0)
+
+    for ((i = 0; i < ${#1}; i++)); do
+        c="${1:$i:1}"
+
+        for ((d = 0; d < 11; d++)); do
+            if [[ ${digits[((d + 1))]} -gt ${digits[$d]} ]]; then
+                for ((e = d; e < 11; e++)); do
+                    n=$((e + 1))
+                    digits[e]=${digits[n]}
+                done
+                digits[11]="0"
+                break
+            fi
+        done
+
+        if [[ $c -gt ${digits[11]} ]]; then
+            digits[11]="$c"
+        fi
+    done
+
+    printf "%s" "${digits[@]}"
+}
+
+total=0
+total2=0
+
+while IFS="" read -r line || [[ -n "$p" ]]; do
+    ((total += $(joltage "$line")))
+    ((total2 += $(joltage2 "$line")))
+done <"$1"
+
+echo "$total"
+echo "$total2"

2025/day04/README.md

@@ -0,0 +1,11 @@
+# Day 04: SQLite sql
+
+Did you know SQLite does not have procedural extensions? I did not when I started this. Regardless,
+to run:
+
+```console
+$ sqlite3 < solve.sql
+part1
+-----
+13
+```

2025/day04/sample.txt

@@ -0,0 +1,10 @@
+..@@.@@@@.
+@@@.@.@.@@
+@@@@@.@.@@
+@.@@@@..@.
+@@.@@@@.@@
+.@@@@@@@.@
+.@.@.@.@@@
+@.@@@.@@@@
+.@@@@@@@@.
+@.@.@@@.@.

2025/day04/solve.sql

@@ -0,0 +1,759 @@
+-- First import raw data into a table so we can work
+CREATE TABLE raw_data(line_data VARCHAR NOT NULL);
+.import --csv './sample.txt' raw_data
+-- Then use the auto-incrementing ID to add a y coordinate
+CREATE TABLE grid_lines(
+    y INTEGER PRIMARY KEY,
+    line_data VARCHAR NOT NULL
+);
+INSERT INTO grid_lines(line_data)
+SELECT line_data
+FROM raw_data;
+-- Now create a table to hold the paper rolls
+CREATE TABLE rolls(
+    x INTEGER NOT NULL,
+    y INTEGER NOT NULL,
+    PRIMARY KEY (x, y)
+);
+WITH RECURSIVE cte AS (
+    SELECT y,
+        1 x,
+        line_data,
+        substr(line_data, 1, 1) c
+    FROM grid_lines
+    UNION ALL
+    SELECT y,
+        x + 1,
+        line_data,
+        substr(line_data, x + 1, 1)
+    FROM cte
+    WHERE x <= length(line_data)
+)
+INSERT INTO rolls
+SELECT x,
+    y
+FROM cte
+WHERE c = '@';
+-- Now compute part 1
+SELECT COUNT(*) as part1
+FROM rolls r
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls o
+        WHERE o.x >= r.x - 1
+            AND o.x <= r.x + 1
+            AND o.y >= r.y - 1
+            AND o.y <= r.y + 1
+    ) < 4;
+--- Create a scratch table where we're going to delete rolls from
+CREATE TABLE rolls2(
+    x INTEGER NOT NULL,
+    y INTEGER NOT NULL,
+    PRIMARY KEY (x, y)
+);
+INSERT INTO rolls2
+SELECT *
+FROM rolls;
+-- Delete the outer rolls of paper 77 times. This turns out to be enough.
+-- I tried really hard not to do this.
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+DELETE FROM rolls2
+WHERE (
+        SELECT COUNT(*) - 1
+        FROM rolls2 o
+        WHERE o.x >= rolls2.x - 1
+            AND o.x <= rolls2.x + 1
+            AND o.y >= rolls2.y - 1
+            AND o.y <= rolls2.y + 1
+    ) < 4;
+-- See how many we've deleted
+SELECT (
+        SELECT COUNT(*)
+        FROM rolls
+    ) - (
+        SELECT COUNT(*)
+        FROM rolls2
+    ) as part2;

2025/day05/.gitignore

@@ -0,0 +1 @@
+solve

2025/day05/Makefile

@@ -0,0 +1,6 @@
+CFLAGS=-Wall -Wextra -O2 -g
+
+all: solve
+
+clean:
+	$(RM) solve

2025/day05/README.md

@@ -0,0 +1,12 @@
+# Day 05: C
+
+C is weird. It's a very simple language but it's made complicated by the fact that you have to do
+everything yourself. Relatively straightforward solution.
+
+```console
+$ make
+cc -Wall -Wextra -O2 -g    solve.c   -o solve
+$ ./solve sample.txt
+Part1: 3
+Part2: 14
+```

2025/day05/sample.txt

@@ -0,0 +1,11 @@
+3-5
+10-14
+16-20
+12-18
+
+1
+5
+8
+11
+17
+32

2025/day05/solve.c

@@ -0,0 +1,160 @@
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+ #define MAX(a,b) \
+    ({ __typeof__ (a) _a = (a); \
+        __typeof__ (b) _b = (b); \
+        _a > _b ? _a : _b; })
+
+typedef struct {
+    uint64_t start;
+    uint64_t end;
+} range_t;
+
+typedef struct {
+    size_t length;
+    size_t capacity;
+    range_t* buffer;
+} ranges_t;
+
+static int cmp_range(void const* va, void const* vb) {
+    range_t const* a = va;
+    range_t const* b = vb;
+
+    if (a->start == b->start) {
+        return (a->end > b->end) - (a->end < b->end);
+    } else {
+        return (a->start > b->start) - (a->start < b-> start);
+    }
+}
+
+static void simplify_ranges(ranges_t* ranges) {
+    // First, sort ranges ascending by start (then end)
+    qsort(ranges->buffer, ranges->length, sizeof(range_t), cmp_range);
+
+    const size_t length = ranges->length;
+    range_t* write_ptr = &ranges->buffer[0];
+
+    // Important, skip the first iteration, it can never be merged
+    for (size_t i = 1; i < length; ++i) {
+        if (ranges->buffer[i].start <= write_ptr->end) {
+            // Merge the two ranges
+            write_ptr->end = MAX(write_ptr->end, ranges->buffer[i].end);
+            ranges->length--;
+        } else {
+            write_ptr++;
+            if (write_ptr != &ranges->buffer[i]) {
+                memcpy(write_ptr, &ranges->buffer[i], sizeof(range_t));
+            }
+        }
+    }
+
+    // for (size_t i = 0; i < ranges->length; ++i) {
+    //     printf("%" PRIu64 "-%" PRIu64 "\n", ranges->buffer[i].start, ranges->buffer[i].end);
+    // }
+
+    // printf("Original length: %u, new length: %u\n", (unsigned int) length, (unsigned int) ranges->length);
+}
+
+bool is_fresh(const uint64_t ingredient, ranges_t const * const ranges) {
+    size_t min = 0;
+    size_t size = ranges->length;
+    range_t const* buffer = ranges->buffer;
+
+    while (size > 1) {
+        size_t half = size / 2;
+        size_t mid = min + half;
+
+        if (buffer[mid].start <= ingredient) {
+            min = mid;
+        }
+
+        size -= half;
+    }
+
+    return buffer[min].start <= ingredient && buffer[min].end >= ingredient;
+}
+
+int main(const int argc, char const** argv) {
+    if (argc < 2) {
+        printf("Usage: %s <input>\n", argv[0]);
+        return 1;
+    }
+
+    ranges_t ranges = {
+        .length = 0,
+        .capacity = 2,
+        .buffer = malloc(2 * sizeof(range_t)),
+    };
+
+    FILE* input = fopen(argv[1], "r");
+    if (input == NULL) {
+        perror("failed to open file");
+        exit(1);
+    }
+
+    uint64_t ingredient;
+    bool seen_first = false;
+
+    while (!seen_first) {
+        uint64_t start;
+        uint64_t end;
+
+        switch (fscanf(input, "%" PRIu64 "-%" PRIu64, &start, &end)) {
+            case 1:
+                seen_first = true;
+                ingredient = start;
+                break;
+
+            case 2:
+                if (ranges.capacity == ranges.length) {
+                    size_t new_capacity = ranges.capacity * 2;
+                    range_t* buffer = realloc(ranges.buffer, new_capacity * sizeof(range_t));
+                    if (buffer == NULL) {
+                        printf("Failed to resize ranges buffer\n");
+                        return 1;
+                    }
+
+                    ranges.capacity = new_capacity;
+                    ranges.buffer = buffer;
+                }
+
+                ranges.buffer[ranges.length].start = start;
+                ranges.buffer[ranges.length].end = end;
+                ranges.length++;
+                break;
+            default:
+                printf("Unexpected end of file\n");
+                return 1;
+        }
+    }
+
+    simplify_ranges(&ranges);
+
+    int total_fresh = 0;
+
+    do {
+        if (is_fresh(ingredient, &ranges)) {
+            total_fresh++;
+        }
+    } while (fscanf(input, "%" PRIu64 "\n", &ingredient) == 1);
+
+    printf("Part1: %u\n", total_fresh);
+
+    uint64_t combined_fresh = 0;
+
+    for (size_t i = 0; i < ranges.length; ++i) {
+        combined_fresh += ranges.buffer[i].end - ranges.buffer[i].start + 1;
+    }
+
+    printf("Part2: %" PRIu64 "\n", combined_fresh);
+
+    fclose(input);
+    free(ranges.buffer);
+
+    return 0;
+}

2025/day06/README.md

@@ -0,0 +1,10 @@
+# Day 06: PHP
+
+Simple and straight-forward. This is a normal programming language.
+
+
+```console
+$ ./solve.php sample.txt
+Part1: 4277556
+Part2: 3263827
+```

2025/day06/sample.txt

@@ -0,0 +1,4 @@
+123 328  51 64 
+ 45 64  387 23 
+  6 98  215 314
+*   +   *   +  

2025/day06/solve.php

@@ -0,0 +1,81 @@
+#!/usr/bin/env php
+<?php
+
+if ($argc < 2) {
+    echo "Usage: {$argv[0]} INPUT\n";
+    exit(1);
+}
+
+$input = file($argv[1]);
+
+function part1(string ...$input): int {
+    $lines = [];
+
+    foreach ($input as $line) {
+        $lines[] = preg_split('/\s+/', $line, -1, PREG_SPLIT_NO_EMPTY);
+    }
+
+    $lines = array_reverse($lines);
+    $cols = count($lines[0]);
+    $rows = count($lines);
+
+    $sum = 0;
+
+    for ($col = 0; $col < $cols; ++$col) {
+        if ($lines[0][$col] === '+') {
+            $acc = 0;
+            for ($row  = 1; $row < $rows; ++$row) {
+                $acc += (int) $lines[$row][$col];
+            }
+        } else {
+            $acc = 1;
+            for ($row  = 1; $row < $rows; ++$row) {
+                $acc *= (int) $lines[$row][$col];
+            }
+        }
+
+        $sum += $acc;
+    }
+
+    return $sum;
+}
+
+function part2(string ...$lines): int {
+    $cols = strlen($lines[0]);
+    $rows = count($lines);
+    $numbers = array_fill(0, $cols, "");
+
+    for ($row = 0; $row < $rows - 1; ++$row) {
+        foreach (str_split($lines[$row]) as $col => $c) {
+            if ($c !== ' ') {
+                $numbers[$col] .= $c;
+            }
+        }
+    }
+
+    $sum = 0;
+
+    foreach (str_split($lines[$rows - 1]) as $col => $c) {
+        switch ($c) {
+            case '+':
+                $acc = 0;
+                for ($i = $col; $i < $cols && $numbers[$i] !== ""; ++$i) {
+                    $acc += (int) $numbers[$i];
+                }
+                $sum += $acc;
+                break;
+            case '*':
+                $acc = 1;
+                for ($i = $col; $i < $cols && $numbers[$i] !== ""; ++$i) {
+                    $acc *= (int) $numbers[$i];
+                }
+                $sum += $acc;
+                break;
+        }
+    }
+
+    return $sum;
+}
+
+echo "Part1: " . part1(...$input) . "\n";
+echo "Part2: " . part2(...$input) . "\n";

2025/day07/.gitignore

@@ -0,0 +1,3 @@
+solve
+*.o
+*.hi

2025/day07/Makefile

@@ -0,0 +1,14 @@
+.PHONY: all clean test
+
+all: solve
+
+test: solve
+	./solve sample.txt
+
+solve: solve.hs
+	ghc -dynamic -O -g -o $@ $^
+
+clean:
+	$(RM) solve
+	$(RM) *.o
+	$(RM) *.hi

2025/day07/README.md

@@ -0,0 +1,15 @@
+# Day 07: Haskell
+
+This one took me the longest, mostly because I really do not know Haskell. Nevertheless, I find the
+resulting solution quite elegant. The `Makefile` I made uses dynamic linkage as that's how Haskell
+works on Arch Linux. If you want to do static linking, `ghc solve.hs` should work.
+
+```console
+$ make
+ghc -dynamic -O -g -o solve solve.hs
+[1 of 2] Compiling Main             ( solve.hs, solve.o )
+[2 of 2] Linking solve
+$ ./solve sample.txt
+21
+40
+```

2025/day07/sample.txt

@@ -0,0 +1,16 @@
+.......S.......
+...............
+.......^.......
+...............
+......^.^......
+...............
+.....^.^.^.....
+...............
+....^.^...^....
+...............
+...^.^...^.^...
+...............
+..^...^.....^..
+...............
+.^.^.^.^.^...^.
+...............

2025/day07/solve.hs

@@ -0,0 +1,65 @@
+import Data.Array
+import Data.List
+import Data.Maybe
+import System.Environment
+import System.Exit
+
+main = getArgs >>= parse >>= run
+
+stringToArray :: [Char] -> Array Int Char
+stringToArray s = listArray (0, length s - 1) s
+
+run :: String -> IO ()
+run input =
+  let gridLines = lines input
+      startingPoint = findStartingPoint $ head gridLines
+      arrLines = Data.List.map stringToArray $ tail gridLines
+   in do
+        print $ part1 arrLines startingPoint
+        print $ part2 arrLines startingPoint
+
+findStartingPoint :: [Char] -> Int
+findStartingPoint line = fromJust $ elemIndex 'S' line
+
+part1 arrLines startingPoint =
+  let initial = [startingPoint]
+   in simulate arrLines 0 initial
+
+checkHit :: Array Int Char -> Int -> [Int]
+checkHit line idx = case line ! idx of
+  '^' -> (idx - 1) : [idx + 1]
+  _ -> [idx]
+
+simulate [] count active = count
+simulate lines count active =
+  let arr = head lines
+      followUp = nub $ concatMap (checkHit arr) active
+      hits = length $ Data.List.filter (\i -> arr ! i == '^') active
+      remainder = tail lines
+   in simulate remainder (hits + count) followUp
+
+part2 :: [Array Int Char] -> Int -> Int
+part2 arrLines startingPosition =
+  let n = length arrLines
+      arr = listArray (0, n - 1) arrLines
+      width = length $ head arrLines
+      compute i pos
+        | i >= n = 1
+        | otherwise =
+            let line = arr ! i
+             in case line ! pos of
+                  '^' -> memo ! (i + 1, pos - 1) + memo ! (i + 1, pos + 1)
+                  _ -> memo ! (i + 1, pos)
+      memo =
+        array
+          ((0, 0), (n, width - 1))
+          [((i, pos), compute i pos) | i <- [0 .. n], pos <- [0 .. width - 1]]
+   in memo ! (0, startingPosition)
+
+parse ["-h"] = usage >> exitSuccess
+parse [] = usage >> die usageStr
+parse fs = concat `fmap` mapM readFile fs
+
+usageStr = "Usage: solve [-vh] [file ..]"
+
+usage = putStrLn usageStr