solutions/0872-leaf-similar-trees.js

/**
 * 872. Leaf-Similar Trees
 * https://leetcode.com/problems/leaf-similar-trees/
 * Difficulty: Easy
 *
 * Consider all the leaves of a binary tree, from left to right order, the values of
 * those leaves form a leaf value sequence.
 *
 * For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).
 *
 * Two binary trees are considered leaf-similar if their leaf value sequence is the same.
 *
 * Return true if and only if the two given trees with head nodes root1 and root2 are
 * leaf-similar.
 */

/**
 * 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} root1
 * @param {TreeNode} root2
 * @return {boolean}
 */
var leafSimilar = function(root1, root2) {
  return traverse(root1, []).toString() === traverse(root2, []).toString();
};

function traverse(root, result) {
  if (!root.left && !root.right) {
    result.push(root.val);
  }
  if (root.left) {
    traverse(root.left, result);
  }
  if (root.right) {
    traverse(root.right, result);
  }
  return result;
}