Same Tree

【题目描述】

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

【思路】

一开始以为只要判断两棵树是否结构相同，wa了一次。

【代码】

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool isSameTree(TreeNode* p, TreeNode* q) {
        if(p==NULL&&q==NULL) return true;
        else if(p==NULL||q==NULL)  return false;
        if(p->val!=q->val) return false;
        bool leftresult=isSameTree(p->left,q->left);
        bool rightresult=isSameTree(p->right,q->right);
        return leftresult&&rightresult;
    }
};