p와 q 둘중하나 null인 경우 처리하는 부분
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
bool isSameTree(TreeNode* p, TreeNode* q) {
if((p==NULL)^(q==NULL))
return false;
if(p==NULL&&q==NULL)
return true;
if(p->val==q->val)
return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);
return false;
}
};