/** * 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} */ const maxDepth = (root) => { let depth = 0; const dfs = (currNode, tmpDepth) => { if (null !== currNode) { tmpDepth++; dfs(currNode.left, tmpDepth); dfs(currNode.right, tmpDepth); } else { depth = Math.max(depth, tmpDepth); return; } } dfs(root, 0); return depth; };