題目描述 從上往下打印出二叉樹的每個(gè)節(jié)點(diǎn)，同層節(jié)點(diǎn)從左至右打印。
import java.util.ArrayList;import java.util.Queue;import java.util.LinkedList;class TreeNode { int val = 0; TreeNode left = null; TreeNode right = null; public TreeNode(int val) { this.val = val; }}public class Solution { public ArrayList<Integer> PRintFromTopToBottom(TreeNode root) { ArrayList<Integer> list = new ArrayList<Integer>(); if(root==null){ return list; } Queue<TreeNode> queue = new LinkedList<TreeNode>(); queue.offer(root); while (!queue.isEmpty()) { TreeNode treeNode = queue.poll(); if (treeNode.left != null) { queue.offer(treeNode.left); } if (treeNode.right != null) { queue.offer(treeNode.right); } list.add(treeNode.val); } return list; }}新聞熱點(diǎn)
疑難解答
