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 List<Integer> list=new ArrayList<>(); public int[] postorderTraversal (TreeNode root) { // write code here postOrder(root); int[] res=new int[list.size()]; for(int i=0;i<list.size();i++){ res[i]=list.get(i); } return res; } public void postOrder(TreeNode root){ if(root==null){ return ; } postOrder(root.left); postOrder(root.right); list.add(root.val); } }