LeetCode BinaryTreeUpsideDown

BinaryTreeUpsideDown.java

import java.util.*;

public class BinaryTreeUpsideDown {
    /**
     * Definition for a binary tree node.
     * public class TreeNode {
     * int val;
     * TreeNode left;
     * TreeNode right;
     * TreeNode(int x) { val = x; }
     * }
     */
    public TreeNode upsideDownBinaryTree(TreeNode root){
        TreeNode cur = root;
        TreeNode new_left = null;
        TreeNode new_right = null;
        TreeNode temp = null;

        while(cur!= null){
            temp = cur.left;
            cur.left = new_left;
            new_left = cur.right;
            cur.right = new_right;
            new_right = cur;
            cur = temp;
        }
        return new_right;
    }
}