add new solutions

solutions/29/q2976/solution.go

@@ -0,0 +1,51 @@
+package q2976
+
+import "math"
+
+const INF int = math.MaxInt
+
+func minimumCost(source string, target string, original []byte, changed []byte, cost []int) int64 {
+	mat := make([][]int, 26)
+	for i := range mat {
+		mat[i] = make([]int, 26)
+		mat[0][i] = INF
+	}
+	for i := 1; i < 26; i++ {
+		copy(mat[i], mat[0])
+	}
+
+	q := make([][3]int, 0, 2*len(original)) // src, dst, cost
+	for i := range original {
+		src, dst, cst := int(original[i]-'a'), int(changed[i]-'a'), cost[i]
+		q = append(q, [3]int{src, dst, cst})
+		mat[src][dst] = min(mat[src][dst], cst)
+	}
+
+	for ; len(q) > 0; q = q[1:] {
+		src, dst, cst := q[0][0], q[0][1], q[0][2]
+		for next := range mat {
+			if next == src || mat[dst][next] == INF {
+				continue
+			}
+			nextCost := mat[dst][next] + cst
+			if nextCost < mat[src][next] {
+				mat[src][next] = nextCost
+				q = append(q, [3]int{src, next, nextCost})
+			}
+		}
+	}
+
+	minTotalCost := 0
+	for i := range len(source) {
+		if source[i] != target[i] {
+			src, dst := source[i]-'a', target[i]-'a'
+			if mat[src][dst] == INF {
+				return -1
+			}
+			minTotalCost += mat[src][dst]
+		}
+	}
+	return int64(minTotalCost)
+}
+
+var _ = minimumCost