/**
 * 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}
 */
export const lowestCommonAncestor = function (root, p, q) {
  if (!root || root === p || root === q) return root
  const left = lowestCommonAncestor(root.left, p, q)
  const right = lowestCommonAncestor(root.right, p, q)
  if ((left === p && right === q) || (left === q && right === p)) return root
  return left || right
}