leetcode binary-tree-inorder-traversal | 二叉树的中序遍历

发表于 2020-12-01 更新于 2022-04-27 分类于 LeetCode-Solutions 阅读次数：
本文字数： 578 阅读时长 ≈ 1 分钟

题目

https://leetcode-cn.com/problems/binary-tree-inorder-traversal/

题解

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public List<Integer> inorderTraversal(TreeNode root) {
        List<Integer> result = new ArrayList<Integer>();
        helper(root, result);
        return result;
    }
    private void helper(TreeNode root, List<Integer> ret) {
        if (root != null) {
            helper(root.left, ret);
            ret.add(root.val);
            helper(root.right, ret);
        }
    }
}