leetcode-100. Same Tree

前言：为了后续的实习面试，开始疯狂刷题，非常欢迎志同道合的朋友一起交流。因为时间比较紧张，目前的规划是先过一遍，写出能想到的最优算法，第二遍再考虑最优或者较优的方法。如有错误欢迎指正。博主首发CSDN，mcf171专栏。

博客链接：mcf171的博客

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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.

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

总结：暂时想到的也只是递归的方式。

----------------更新于2016/10/14-----------------

现在看之前写的代码挺2的，服务器貌似好了，多次提交每次的rank基本不变了。Your runtime beats 18.94% of java submissions.

public class Solution {    public boolean isSameTree(TreeNode p, TreeNode q) {        if(p == null && q == null) return true;if( p != null && q != null){boolean flag = p.val == q.val;if(flag) flag = isSameTree(p.left,q.left);if(flag) flag = isSameTree(p.right,q.right);return flag;}return false;    }}