[LeetCode] 100. Same Tree

传送门

Description

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.

思路

题意：给出两棵二叉搜索树，判断这两棵二叉搜索树是否相同

题解：前序遍历+中序遍历或后序遍历+中序遍历可以完全确定一颗二叉搜索树（数据中第52组：[1,null,1] [1,1]，此种写法挂在了这里）；或者直接递归搜索的过程判断。

 

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/**  * Definition for a binary tree node.  * public class TreeNode {  *     int val;  *     TreeNode left;  *     TreeNode right;  *     TreeNode(int x) { val = x; }  * }  */ class Solution {     public boolean isSameTree(TreeNode p, TreeNode q) {         if (p == null && q == null) return true;         if (p == null || q == null) return false;         if (p.val == q.val) return isSameTree(p.left,q.left) && isSameTree(p.right,q.right);         else    return false;     } }