[LeetCode]Same Tree

Same Tree

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.

递归实现代码写的比较简洁，循环需要用到stack。

 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     bool isSameTree(TreeNode* p, TreeNode* q) {
13         if(!p && !q) return true;
14         if(!p || !q) return false;
15         return p->val==q->val && isSameTree(p->left,q->left) && isSameTree(p->right,q->right);
16     }
17 };