题解 | #二叉树的中序遍历#

import java.util.*;

/*

• public class TreeNode {
• int val = 0;
• TreeNode left = null;
• TreeNode right = null;
• public TreeNode(int val) {

• this.val = val;
  

• }
• } */

public class Solution { /** * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可 * * * @param root TreeNode类 * @return int整型一维数组 */ public int[] inorderTraversal (TreeNode root) { // write code here List list = new ArrayList<>(); int[] ans = new int[list.size()]; if(root == null) return ans; list = inOrder(root,list); int[] res = new int[list.size()]; for(int i = 0;i < list.size();i++){ res[i] = list.get(i); } return res; } public List inOrder(TreeNode root,List list){ if(root == null) return null; inOrder(root.left,list); list.add(root.val); inOrder(root.right,list); return list; } }