[Leetcode] [Java] Flatten Binary Tree to Linked List

Title:

Given a binary tree, flatten it to a linked list in-place.

For example,
Given

         1        /        2   5      /\        3   4   6

The flattened tree should look like:

   1         2             3                 4                     5                         6

Test Instructions:

Given a binary tree, it turns itself into a single-linked list.

For example, given

         1        /        2   5      /\        3   4   6

transformed into a flat tree as shown:

   1         2             3                 4                     5                         6

Algorithm Analysis:

* This method directly on root node, first temporarily save the left and right subtree, if Root has a left dial hand tree, the root.right attached to the root.left,root.left to null, and then on the left subtree of the tree

* Find rightmost node and put the right subtree before it on the rightmost.right.

* Once done, the left subtree of root has been grafted between the right subtree and root, and the original left subtree becomes null and can be root.right recursively.

AC Code:

<span style= "Font-family:microsoft yahei;font-size:12px;" >/** * Definition for Binary tree * public class TreeNode {*     int val, *     TreeNode left, *     TreeNode right;     TreeNode (int x) {val = x;} *} */public class Solution {public    void flatten (TreeNode root)     {        if (root = = null) return;        if (root.left! = null)        {            TreeNode left = root.left;            TreeNode right = Root.right;            Root.left = null;            Root.right = left;            TreeNode rightmost = root.right;            while (rightmost.right! = null)            {                rightmost = rightmost.right;            }            Rightmost.right = right;        }        Flatten (root.right);    }} </span>

Copyright NOTICE: This article is the original article of Bo Master, reprint annotated source

[Leetcode][java] Flatten Binary Tree to Linked List