src/main/java/com/fishercoder/solutions/_114.java

package com.fishercoder.solutions;

import com.fishercoder.common.classes.TreeNode;

public class _114 {

    public static class Solution1 {
        public void flatten(TreeNode root) {
            while (root != null) {
                if (root.left != null) {
                    TreeNode previousNode = root.left;
                    while (previousNode.right != null) {
                        previousNode = previousNode.right;
                    }
                    previousNode.right = root.right;
                    root.right = root.left;
                    root.left = null;
                }
                root = root.right;
            }
        }
    }
}