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; } };