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.
class Solution {
public:
bool isSameTree(TreeNode *p, TreeNode *q) {
if(p==NULL && q==NULL) return true;
else if(p==NULL || q==NULL) return false;
else if(p->val != q->val)return false;
return isSameTree(p->left,q->left) && isSameTree(p->right,q->right);
}
};
