相同的树

解法一：递归

js实现

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} p
 * @param {TreeNode} q
 * @return {boolean}
 */
var isSameTree = function (p, q) {
  if (!p && !q) return true
  if ((p && !q) || (!p && q) || (p && q && p.val !== q.val)) return false

  return isSameTree(p.left, q.left) && isSameTree(p.right, q.right)
};