/**
* 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 {
bool isSameTree(TreeNode* s, TreeNode* t){
if(!s && !t) return true;
if((!s&&t) || (s&&!t)) return false;
if(s->val==t->val)
return isSameTree(s->left,t->left) && isSameTree(s->right,t->right);
return false;
}
public:
bool isSubtree(TreeNode* s, TreeNode* t) {
if(!t) return true;
if(!s && t) return false;
return isSameTree(s,t) || isSubtree(s->left,t) || isSubtree(s->right,t);
}
};