Leetcode:Same Tree 判断相同二叉树

戳我去解题

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.

 

 

分析：对于二叉树这一具有天然递归特性的数据结构，首先想到的就应该是递归，既然是递归，最重要就是边界了

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