Chain reaction solution in Go uploaded - Apprentice 2023A

solutions/chain-reactions/Go/chainReaction.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+// Just for the reading of the test cases
+func main() {
+	var T int
+	fmt.Scanf("%d", &T)
+
+	for caseNumber := 1; caseNumber <= T; caseNumber++ {
+		var N int
+		fmt.Scanf("%d", &N)
+
+		F := make([]int64, N+1)
+		for i := 1; i < N+1; i++ {
+			fmt.Scanf("%d", &F[i])
+		}
+
+		P := make([]int64, N+1)
+		for i := 1; i < N+1; i++ {
+			fmt.Scanf("%d", &P[i])
+		}
+
+		// Machines that point to each other
+		machines := make(map[int64][]int64)
+		for i := 1; i < N+1; i++ {
+			machines[P[i]] = append(machines[P[i]], int64(i))
+		}
+
+		Fun, _ := chainReaction(0, machines, F)
+		fmt.Printf("Case #%d: %d\n", caseNumber, Fun)
+	}
+}
+
+// The solution of the actual problem
+func chainReaction(root int64, machines map[int64][]int64, F []int64) (maxF int64, minV int64) {
+	if len(machines[root]) == 0 {
+		return F[root], F[root]
+	} else {
+		maxF = 0
+		minV = math.MaxInt64
+		for _, machine := range machines[root] {
+			total, low := chainReaction(machine, machines, F)
+			maxF += total
+			minV = int64(math.Min(float64(minV), float64(low)))
+		}
+	}
+
+	if minV < int64(F[root]) {
+		maxF += F[root] - minV
+		minV = F[root]
+	}
+
+	return
+}