leetcode—Same Tree

1.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.

2.解法分析

与上一篇文章“Symmetric Tree”一样的思路，只是要证明两棵树完全一样，需对两棵树进行一模一样的遍历。当然最好是深度搜索。

/**

 * Definition for binary tree

 * 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) {

        // Start typing your C/C++ solution below

        // DO NOT write int main() function

        vector<TreeNode *> vp;

        vector<TreeNode *> vq;

        TreeNode *curp= p;

        TreeNode *curq =q;

        while(curp||!vp.empty())

        {

            while(curp)

            {

                if(!curq)return false;

                if(curp->val!=curq->val)return false;

                vp.push_back(curp);

                vq.push_back(curq);

                curp=curp->left;

                curq=curq->left;

            }

            if(!vp.empty())

            {

                if(curp)return false;

                curp=vp.back();vp.pop_back();curp=curp->right;

                curq=vq.back();vq.pop_back();curq=curq->right;

            }

        }

        if((vp.empty()&&!vq.empty())||(!vp.empty()&&vq.empty()))return false;

        if((curp&&!curp)||(!curp&&curq))return false;

        return true;

    }

};