题解 | #二叉树的后序遍历#
二叉树的后序遍历
https://www.nowcoder.com/practice/1291064f4d5d4bdeaefbf0dd47d78541
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
*/
private void recursivelyPostorder(TreeNode vroot, List<Integer> temp){
if(vroot.left!=null) recursivelyPostorder(vroot.left, temp);
if(vroot.right !=null) recursivelyPostorder(vroot.right, temp);
temp.add(vroot.val);
}
public int[] postorderTraversal (TreeNode root) {
// write code here
if(root==null){
int[] treeList = new int[0];
return treeList;
}
List<Integer> temp = new ArrayList();
recursivelyPostorder(root, temp);
int[] treeList = new int[temp.size()];
for(int i=0;i<temp.size();i++){
treeList[i] = temp.get(i);
}
return treeList;
}
}
投递三维家等公司10个岗位
查看3道真题和解析