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.

Subscribe to see which companies asked this question

很简单的题目，但是对不成立的情况需要考虑清楚以免第一次写错。


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