Same Tree

废话不多说，直接上代码，哈哈，痛快：

/** * 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)            return true;        if(p == NULL && q != NULL)            return false;        if(p != NULL && q == NULL)            return false;        //establish a recursive relation           if(p->val != q->val)            return false;        return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);    }};