Implement day 13 in Go.

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)
+}