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) {}
 * };
 */

运用递归
class Solution {
public:
    bool isSameTree(TreeNode* p, TreeNode* q) {
     if (p ==NULL&& q ==NULL)
     return true;
     if (p ==NULL|| q ==NULL)
     return false;
     else
     {
     if(p->val != q->val )
     return false;
     else
     return isSameTree(p->left,q->left) && isSameTree(p->right,q->right);
     }
       
    }
};