add sol

leetcode/563.BinaryTreeTilt/binaryTreeTilt.go

@@ -0,0 +1,40 @@
+package main
+
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func findTilt(root *TreeNode) int {
+	result := 0
+	dfs(root, &result)
+	return result
+}
+
+func dfs(root *TreeNode, result *int) int {
+	if root == nil {
+		return 0
+	}
+	left, right := dfs(root.Left, result), dfs(root.Right, result)
+	*result += abs(left - right)
+	return root.Val + right + left
+}
+
+func abs(a int) int {
+	if a > 0 {
+		return a
+	}
+	return -a
+}
+
+func main() {}