# 100. Same Tree (Easy)

## 1.問題 

* 給予兩個binary tree, 決定是否相同

![](https://901207480-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LGKoChvN9am4__HCIRK%2F-LHwwabBkk4ws8YCysB8%2F-LHwy5nCMWx9AalOC573%2F201872101.jpg?alt=media\&token=798edccd-a225-477c-b1b5-59d7f2a5dad5)

## 2.想法 

* Recursive + back tracking

## 3.程式碼

```
/**
 * 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 && !q) {
            return true;
        }
        
        if (!p || !q) {
            return false;
        }
        
        if (p->val == q->val) {
            return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
        }
        
        return false;
    }
};
```

## 4.Performance

![](https://901207480-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LGKoChvN9am4__HCIRK%2F-LHwwabBkk4ws8YCysB8%2F-LHwyq2gqpBU_52lXf6Z%2F201872102.jpg?alt=media\&token=e977b452-60bd-421c-bfbe-434a6e3c3341)