#559 - Maximum Depth of N-ary Tree

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Problem Description

Given a n-ary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

Nary-Tree input serialization is represented in their level order traversal, each group of children is separated by the null value (See examples).

Solution

/**
 * // Definition for a _Node.
 * function _Node(val,children) {
 *    this.val = val === undefined ? null : val;
 *    this.children = children === undefined ? null : children;
 * };
 */

/**
 * @param {_Node|null} root
 * @return {number}
 */
var maxDepth = function(root) {
  if (!root) return 0;
  if (!root.children || !root.children.length) return 1;
  return Math.max(...root.children.map(child => maxDepth(child))) + 1;
};