[hard]daily:834

solution/834/main.go

@@ -0,0 +1,42 @@
+package main
+
+package main
+
+func sumOfDistancesInTree(n int, edges [][]int) []int {
+	graph := make(map[int][]int)
+	count := make([]int, n)
+	res := make([]int, n)
+
+	for _, edge := range edges {
+		u, v := edge[0], edge[1]
+		graph[u] = append(graph[u], v)
+		graph[v] = append(graph[v], u)
+	}
+
+	var dfs1 func(cur, parent int)
+	dfs1 = func(cur, parent int) {
+		count[cur] = 1
+		for _, child := range graph[cur] {
+			if child != parent {
+				dfs1(child, cur)
+				count[cur] += count[child]
+				res[cur] += res[child] + count[child]
+			}
+		}
+	}
+
+	var dfs2 func(cur, parent int)
+	dfs2 = func(cur, parent int) {
+		for _, child := range graph[cur] {
+			if child != parent {
+				res[child] = res[cur] + n - 2*count[child]
+				dfs2(child, cur)
+			}
+		}
+	}
+
+	dfs1(0, -1)
+	dfs2(0, -1)
+
+	return res
+}