把二叉树打印成多行
2019-03-12 17:39 YihangZhou 阅读(161) 评论(0) 编辑 收藏 举报题目描述
从上到下按层打印二叉树,同一层结点从左至右输出。每一层输出一行。
import java.util.ArrayList; /* public class TreeNode { int val = 0; TreeNode left = null; TreeNode right = null; public TreeNode(int val) { this.val = val; } } */ public class Solution { ArrayList<ArrayList<Integer> > Print(TreeNode pRoot) { ArrayList<ArrayList<Integer>> list = new ArrayList<>(); depth(pRoot, 1, list); return list; } public void depth(TreeNode node, int depth, ArrayList<ArrayList<Integer>> list) { if(node == null) return; if(depth > list.size()) list.add(new ArrayList<Integer>()); list.get(depth-1).add(node.val); depth(node.left, depth + 1, list); depth(node.right, depth + 1, list); } }