Implement 2019 day 14

2019/aoc2019/day14.py

@@ -0,0 +1,71 @@
+import math
+from collections import defaultdict
+from typing import TextIO, Tuple
+
+from networkx import DiGraph, topological_sort
+
+
+def read_pair(item: str) -> Tuple[str, int]:
+    amount, element = item.split(' ')
+
+    return element, int(amount)
+
+
+def read_recipes(data: TextIO) -> DiGraph:
+    graph = DiGraph()
+
+    for line in data:
+        requisites, production = line.strip().split(' => ')
+
+        produced, produced_amount = read_pair(production)
+        graph.add_node(produced, weight=produced_amount)
+
+        for requisite in requisites.split(', '):
+            required, required_amount = read_pair(requisite)
+            graph.add_edge(produced, required, weight=required_amount)
+
+    return graph
+
+
+def ore_required(graph: DiGraph, fuel_required: int) -> int:
+    requirements = defaultdict(int)
+    requirements['FUEL'] = fuel_required
+
+    for element in topological_sort(graph):
+        if element not in requirements:
+            continue
+
+        if element == 'ORE':
+            break
+
+        element_produced = graph.nodes[element]['weight']
+        productions_required = math.ceil(requirements[element] / element_produced)
+
+        for _, elem_required, amount_required in graph.edges(element, data='weight'):
+            requirements[elem_required] += amount_required * productions_required
+
+    return requirements['ORE']
+
+
+def part1(data: TextIO) -> int:
+    return ore_required(read_recipes(data), 1)
+
+
+def part2(data: TextIO) -> int:
+    ore_available = 1000000000000
+    graph = read_recipes(data)
+
+    min_possible = 1  # lower bound of ORE / ore_required(graph, 1) exists but is slower
+    max_possible = ore_available
+
+    while min_possible != max_possible:
+        check = min_possible + (max_possible - min_possible + 1) // 2
+
+        required = ore_required(graph, check)
+
+        if required <= ore_available:
+            min_possible = check
+        else:
+            max_possible = check - 1
+
+    return min_possible

2019/tests/test_day14.py

@@ -0,0 +1,80 @@
+from io import StringIO
+from textwrap import dedent
+
+import pytest
+
+from aoc2019.day14 import part1, part2
+
+SAMPLES = [
+    dedent("""\
+    9 ORE => 2 A
+    8 ORE => 3 B
+    7 ORE => 5 C
+    3 A, 4 B => 1 AB
+    5 B, 7 C => 1 BC
+    4 C, 1 A => 1 CA
+    2 AB, 3 BC, 4 CA => 1 FUEL
+    """),
+    dedent("""\
+    157 ORE => 5 NZVS
+    165 ORE => 6 DCFZ
+    44 XJWVT, 5 KHKGT, 1 QDVJ, 29 NZVS, 9 GPVTF, 48 HKGWZ => 1 FUEL
+    12 HKGWZ, 1 GPVTF, 8 PSHF => 9 QDVJ
+    179 ORE => 7 PSHF
+    177 ORE => 5 HKGWZ
+    7 DCFZ, 7 PSHF => 2 XJWVT
+    165 ORE => 2 GPVTF
+    3 DCFZ, 7 NZVS, 5 HKGWZ, 10 PSHF => 8 KHKGT
+    """),
+    dedent("""\
+    2 VPVL, 7 FWMGM, 2 CXFTF, 11 MNCFX => 1 STKFG
+    17 NVRVD, 3 JNWZP => 8 VPVL
+    53 STKFG, 6 MNCFX, 46 VJHF, 81 HVMC, 68 CXFTF, 25 GNMV => 1 FUEL
+    22 VJHF, 37 MNCFX => 5 FWMGM
+    139 ORE => 4 NVRVD
+    144 ORE => 7 JNWZP
+    5 MNCFX, 7 RFSQX, 2 FWMGM, 2 VPVL, 19 CXFTF => 3 HVMC
+    5 VJHF, 7 MNCFX, 9 VPVL, 37 CXFTF => 6 GNMV
+    145 ORE => 6 MNCFX
+    1 NVRVD => 8 CXFTF
+    1 VJHF, 6 MNCFX => 4 RFSQX
+    176 ORE => 6 VJHF
+    """),
+    dedent("""\
+    171 ORE => 8 CNZTR
+    7 ZLQW, 3 BMBT, 9 XCVML, 26 XMNCP, 1 WPTQ, 2 MZWV, 1 RJRHP => 4 PLWSL
+    114 ORE => 4 BHXH
+    14 VRPVC => 6 BMBT
+    6 BHXH, 18 KTJDG, 12 WPTQ, 7 PLWSL, 31 FHTLT, 37 ZDVW => 1 FUEL
+    6 WPTQ, 2 BMBT, 8 ZLQW, 18 KTJDG, 1 XMNCP, 6 MZWV, 1 RJRHP => 6 FHTLT
+    15 XDBXC, 2 LTCX, 1 VRPVC => 6 ZLQW
+    13 WPTQ, 10 LTCX, 3 RJRHP, 14 XMNCP, 2 MZWV, 1 ZLQW => 1 ZDVW
+    5 BMBT => 4 WPTQ
+    189 ORE => 9 KTJDG
+    1 MZWV, 17 XDBXC, 3 XCVML => 2 XMNCP
+    12 VRPVC, 27 CNZTR => 2 XDBXC
+    15 KTJDG, 12 BHXH => 5 XCVML
+    3 BHXH, 2 VRPVC => 7 MZWV
+    121 ORE => 7 VRPVC
+    7 XCVML => 6 RJRHP
+    5 BHXH, 4 VRPVC => 5 LTCX
+    """),
+]
+
+
+@pytest.mark.parametrize("sample,correct", zip(SAMPLES, [165, 13312, 180697, 2210736]))
+def test_part1(sample: str, correct: int):
+    data = StringIO(sample)
+
+    result = part1(data)
+
+    assert result == correct
+
+
+@pytest.mark.parametrize("sample,correct", zip(SAMPLES[1:], [82892753, 5586022, 460664]))
+def test_part2(sample: str, correct: int):
+    data = StringIO(sample)
+
+    result = part2(data)
+
+    assert result == correct