Leetcode100.相同的树

题目描述
 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 8  *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 9  *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
10  * };
11  */
12  
13 class Solution {
14 public:
15     bool isSameTree(TreeNode* p, TreeNode* q) {
16         if (p == nullptr && q == nullptr) {
17             return true;
18         } else if (p == nullptr || q == nullptr) {
19             return false;
20         } else if (p->val != q->val) {
21             return false;
22         } else {
23             return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
24         }
25         }
26 };