Added 110. Balanced Binary Tree

Author: berkslv

javascript/110-Balanced-Binary-Tree.js

@@ -0,0 +1,26 @@
+/**
+ * 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 {boolean}
+ */
+ var isBalanced = function (root) {
+    if (!root) return true
+    const left = findHeight(root.left)
+    const right = findHeight(root.right)
+    return Math.abs(left - right) <= 1 && isBalanced(root.left) && isBalanced(root.right)
+};
+
+function findHeight(node) {
+    if (node == null) return 0;
+    return 1 + Math.max(this.findHeight(node.left), this.findHeight(node.right));
+}
+
+// Runtime: 78 ms, faster than 90.43% of JavaScript online submissions for Balanced Binary Tree.
+// Memory Usage: 47.1 MB, less than 32.41% of JavaScript online submissions for Balanced Binary Tree.