题解 | #二叉树的中序遍历#
二叉树的中序遍历
http://www.nowcoder.com/practice/0bf071c135e64ee2a027783b80bf781d
简单递归解决中序遍历
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 */ ArrayList<Integer> list = new ArrayList<>(); public int[] inorderTraversal (TreeNode root) { // write code here inorder(root); int[] res = new int[list.size()]; int index = 0; for (int num : list) { res[index] = list.get(index++); } return res; } private void inorder(TreeNode node) { if (node != null) { inorder(node.left); list.add(node.val); inorder(node.right); } } }