package code;

import java.util.ArrayList;
import java.util.List;


public class TreeFlatten {
	static public class TreeNode {
	 int val;
	 TreeNode left;
	 TreeNode right;
	 TreeNode(int x) { val = x; }
	}
	
	public void dfs(TreeNode p,List<TreeNode> list){
		if(p==null)	return ;
		list.add(p);
		dfs(p.left,list);
		dfs(p.right,list);
		
	}
 public void flatten(TreeNode root) {
 if(root==null)	return;
 List<TreeNode> list=new ArrayList<TreeNode>();
 TreeNode p=root;
 dfs(p,list);
 for(int i=0;i<list.size()-1;i++){
 	p=list.get(i);
 	p.right=list.get(i+1);
 	p.left=null;
 }
 }
 
 public static void main(String[] args){
 	
 }
}