4.5 leetcode -5 same-tree

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

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

完全是第四题的子函数。。

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