Add solution #563

Author: JoshCrozier

README.md

@@ -170,6 +170,7 @@
 542|[01 Matrix](./0542-01-matrix.js)|Medium|
 551|[Student Attendance Record I](./0551-student-attendance-record-i.js)|Easy|
 557|[Reverse Words in a String III](./0557-reverse-words-in-a-string-iii.js)|Easy|
+563|[Binary Tree Tilt](./0563-binary-tree-tilt.js)|Easy|
 565|[Array Nesting](./0565-array-nesting.js)|Medium|
 566|[Reshape the Matrix](./0566-reshape-the-matrix.js)|Easy|
 567|[Permutation in String](./0567-permutation-in-string.js)|Medium|

solutions/0563-binary-tree-tilt.js

@@ -0,0 +1,38 @@
+/**
+ * 563. Binary Tree Tilt
+ * https://leetcode.com/problems/binary-tree-tilt/
+ * Difficulty: Easy
+ *
+ * Given the root of a binary tree, return the sum of every tree node's tilt.
+ *
+ * The tilt of a tree node is the absolute difference between the sum of all
+ * left subtree node values and all right subtree node values. If a node does
+ * not have a left child, then the sum of the left subtree node values is
+ * treated as 0. The rule is similar if the node does not have a right child.
+ */
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var findTilt = function(root) {
+  const result = { val: 0 };
+  dfs(root, result);
+  return result.val;
+};
+
+function dfs(root, tilt) {
+  if (!root) return 0;
+  const left = dfs(root.left, tilt);
+  const right = dfs(root.right, tilt);
+  tilt.val += Math.abs(left - right);
+  return root.val + left + right;
+}