Leetcode 100. Same Tree

Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical and the nodes have the same value.

Example 1:

Example 2:

用递归方法，分别判断左右子树是否相同

/**
 * 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 (NULL == p && NULL == q)
        {   
            return true;
        }   
        else if (NULL != p && NULL != q)
        {   
            if (p->val != q->val)
            {   
                return false;
            }   
            return this->isSameTree(p->left, q->left) && this->isSameTree(p->right, q->right);
        }   
        else
        {   
            return false;
        }   
    }   
};