[LeetCode]Flatten Binary Tree to Linked List

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

参考     戴方勤 ([e-mail])     https://github.com/soulmachine/leetcode

/** * 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;        flatten(root.left);        flatten(root.right);        if(root.left == null) return;                TreeNode p = root.left;        while(p.right!=null) p = p.right;        p.right = root.right;        root.right = root.left;        root.left = null;    }}