题解 | #二叉树的中序遍历#
二叉树的中序遍历
https://www.nowcoder.com/practice/0bf071c135e64ee2a027783b80bf781d
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 Stack<TreeNode> stack = new Stack<>(); ArrayList<Integer> list = new ArrayList<>(); TreeNode cur = root; //用一个指针 while(cur != null || !stack.isEmpty()){ if(cur != null){ stack.push(cur); cur = cur.left; }else{ cur = stack.pop(); list.add(cur.val); cur = cur.right; } } int []arr = new int[list.size()]; for(int i = 0 ; i < list.size() ; i++){ arr[i] = list.get(i); } return arr; } }