题目描述

给定一个无序单链表，实现单链表的排序(按升序排序)。

示例1

输入

[1,3,2,4,5]

返回值

{1,2,3,4,5}

 

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 * }
 */

public class Solution {
    /**
     * 
     * @param head ListNode类 the head node
     * @return ListNode类
     */
    public ListNode sortInList (ListNode head) {
       
        if(head == null || head.next == null){
            return head;
        }
        
        int len = 0;
        ListNode tempNode = head;
        while(tempNode!=null){
            len++;
            tempNode = tempNode.next;
        }
        
        int[] arr = new int[len];
        ListNode tempNode2 = head;
        for(int i=0;i<len;i++){
            arr[i] = tempNode2.val;
            tempNode2 = tempNode2.next;
        }
        
        Arrays.sort(arr);
        
        int j = 0;
        ListNode tempNode3 = head;
        while(tempNode3!=null){
            tempNode3.val = arr[j++];
            tempNode3 = tempNode3.next;
        }
        
        return head;
    }
}