LeetCode——Same Tree（判断两棵树是否相同）

问题：

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.

分析：

考虑使用深度优先遍历的方法，同时遍历两棵树，遇到不等的就返回。

代码如下：

/**
 * Definition for binary tree
 * 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 p==q;
        }
        if(p.val != q.val){
            return false;
        }
        return isSameTree(p.left,q.left)&& isSameTree(p.right,q.right);
    }
}