package Booleans;

import Entitys.TreeNode;

import org.junit.Test;

/**

* @description: 描述 Easy Same Tree

* @author: dekai.kong

* @date: 2019-01-29 14:01

* @from https://leetcode.com/problems/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:

*

* Input: 1 1

* / \ / \

* 2 3 2 3

*

* [1,2,3], [1,2,3]

*

* Output: true

* Example 2:

*

* Input: 1 1

* / \

* 2 2

*

* [1,2], [1,null,2]

*

* Output: false

* Example 3:

*

* Input: 1 1

* / \ / \

* 2 1 1 2

*

* [1,2,1], [1,1,2]

*

* Output: false

*/

public class SameTree {

public SameTree() {

}

/**

* Runtime: 2 ms, faster than 100.00% of Java online submissions for Same Tree.

* @param p

* @param q

* @return

* 递归 前序遍历

*/

public boolean isSameTree(TreeNode p, TreeNode q) {

return helper(p,q);

}

public boolean helper(TreeNode p, TreeNode q){

if(p!=null && q!=null){

boolean a = p.val==q.val;

if(!a) return false;

boolean b = helper(p.left,q.left);

if(!b) return false;

boolean c = helper(p.right,q.right);

if(!c) return false;

if(a && b && c) return true;

}else if(p==q) {

return true;

}

return false;

}

@Test

public void test() {

TreeNode p = new TreeNode(1);

p.left = null;

TreeNode right = new TreeNode(2);

right.left = new TreeNode(3);

p.right = right;

TreeNode q = new TreeNode(1);

q.left = null;

TreeNode rightq = new TreeNode(2);

rightq.left = new TreeNode(3);

q.right = rightq;

System.out.println(isSameTree(p,q));

}

}