236.lowest-common-ancestor-of-a-binary-tree.js

/*
 * @lc app=leetcode id=236 lang=javascript
 *
 * [236] Lowest Common Ancestor of a Binary Tree
 */

// @lc code=start
/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @param {TreeNode} p
 * @param {TreeNode} q
 * @return {TreeNode}
 */
var lowestCommonAncestor = function(root, p, q) {
  if (!root || p === root || q === root) return root
  const left = lowestCommonAncestor(root.left, p, q)
  const right = lowestCommonAncestor(root.right, p, q)
  if (left && right) return root
  return left ? left : right
};
// @lc code=end