leetcode：Same Tree 【Java】

一、问题描述

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

二、问题分析

递归比较左右子树结构以及结点的值是否相同。

三、算法代码

/** * Definition for a binary tree node. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public boolean isSameTree(TreeNode p, TreeNode q) {        if(p == null && q == null){            return true;        }        if(p == null || q == null){            return false;        }                return (p.val == q.val) && isSameTree(p.left, q.left) && isSameTree(p.right, q.right);    }}