【LeetCode】100 - 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.

Solution 1：递归，关键在于找全return true、false的所有条件

 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)
14             return true;
15         else if(!p&&q)
16             return false;
17         else if(p&&!q)
18             return false;
19         else{
20             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 };

Solution 2: 非递归，待续