leetcode之same tree

/**
 * Definition for binary tree
 * 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) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(p == NULL && q==NULL) {
            return true;
        }
        if (p==NULL&&q!=NULL || p!=NULL&&q==NULL) {
            return false;
        }
        bool res = false;
        if (p->val != q->val) {
            res = false;
        } else {
            bool leftTree = isSameTree(p->left, q->left);
            bool rightTree = isSameTree(p->right, q->right);
            res = leftTree&&rightTree;
        }
        return res;
    }
};