100. Same Tree lnk

//https://leetcode.com/problems/same-tree/
/**
 * 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 res = 1;
    bool isSameTree(TreeNode* p, TreeNode* q) {
        if(p && q)
            if(p->val != q->val)
                res = 0;
            else{
                isSameTree(p->left,q->left);
                isSameTree(p->right,q->right);
            }
        else     if(p || q)res = 0;
        return res;
        
    }
};