검지offer 면접문제 60 두 갈래 트리를 여러 줄로 인쇄(Java 구현)

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;


class TreeNode {
	int val = 0;
	TreeNode left = null;
	TreeNode right = null;

	public TreeNode(int val) {
		this.val = val;

	}

}

public class Solution {

	ArrayList> Print(TreeNode pRoot) {
		
		ArrayList> arrayList = new ArrayList>();
		if (pRoot == null) {
			return arrayList;
		}
		Queue queue = new LinkedList();
		
		queue.add(pRoot);
		
		ArrayList arrayListlayer = new ArrayList<>();
		
		int start = 0;
		int end = 1;
		
		while (!queue.isEmpty()) {
			TreeNode cur = queue.remove();
			
			arrayListlayer.add(cur.val);
			
			start++;
			
			TreeNode left = cur.left;
			TreeNode right = cur.right;
			
			if (left != null) {
				queue.add(left);
			}
			
			if (right != null) {
				queue.add(right);
				
			}
			
			if (start == end) {
				end = queue.size();
				start = 0;
				arrayList.add(arrayListlayer);
				arrayListlayer = new ArrayList<>();
			}
		}
		
		return arrayList;
		
	}

}