/**

 * 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 isSameTree(TreeNode* p, TreeNode* q) {

        if ((p==NULL&&q!=NULL)||(q==NULL&&p!=NULL)) return false;

        if (p==NULL && q==NULL) return true;

        if (p->val != q->val) return false;

        else return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);

        /*

        if (p->left != NULL && q->left != NULL){

            if (p->left->val != q->left->val) return false;

            isSameTree(p->left,q->left);

        }

        if (p->right != NULL && q->right != NULL){

            if (p->right->val != q->right->val) return false;

            isSameTree(p->right,q->right);

        }

        //一个大错特错的递归…………

        */

        //return true;

    }

};