Implement day 13 in Go.

2017/README.md

@@ -13,6 +13,7 @@ The current plan, in no particular order:
 - [x] C# - [Day 07](./day-07/solution.cs)
 - [x] Clojure - [Day 03](./day-03/solution.clj)
 - [ ] Coffeescript
+- [x] Go - [Day 13](./day-13/solution.go)
 - [ ] Haskell
 - [ ] Java
 - [x] Kotlin - [Day 10](./day-10/solution.kt)

2017/day-13/input.txt

@@ -0,0 +1,43 @@
+0: 3
+1: 2
+2: 4
+4: 6
+6: 4
+8: 6
+10: 5
+12: 6
+14: 8
+16: 8
+18: 8
+20: 6
+22: 12
+24: 8
+26: 8
+28: 10
+30: 9
+32: 12
+34: 8
+36: 12
+38: 12
+40: 12
+42: 14
+44: 14
+46: 12
+48: 12
+50: 12
+52: 12
+54: 14
+56: 12
+58: 14
+60: 14
+62: 14
+64: 14
+70: 10
+72: 14
+74: 14
+76: 14
+78: 14
+82: 14
+86: 17
+88: 18
+96: 26

2017/day-13/solution.go

@@ -0,0 +1,54 @@
+package main
+
+import "fmt"
+
+func read_input() map[int]int {
+	var level, depth int
+
+	var result = make(map[int]int)
+
+	for {
+		if n, err := fmt.Scanf("%d: %d", &level, &depth); n != 2 || err != nil {
+			break
+		}
+
+		result[level] = depth
+	}
+
+	return result
+}
+
+func penalty(firewalls map[int]int) int {
+	var score = 0
+
+	for level, depth := range firewalls {
+		if level % (2 * depth - 2) == 0 {
+			score += level * depth
+		}
+	}
+
+	return score
+}
+
+func caught(firewalls map[int]int, offset int) bool {
+	for level, depth := range firewalls {
+		if (level + offset) % (2 * depth - 2) == 0 {
+			return true
+		}
+	}
+
+	return false
+}
+
+func main() {
+	firewalls := read_input()
+
+	fmt.Printf("Penalty: %d\n", penalty(firewalls))
+
+	var offset = 1
+
+	for ; caught(firewalls, offset); offset++ {
+	}
+
+	fmt.Printf("Wait time: %d\n", offset)
+}