题解 | #单链表的排序#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(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 head ListNode类 the head node
     * @return ListNode类
     */
    public ListNode sortInList (ListNode head) {
        // write code here
        if(head == null) {
            return null;
        }

        List<Integer> list = new ArrayList<>();
        
        ListNode loop = head;
        while(loop != null) {
            list.add(loop.val);
            loop = loop.next;
        }
        list.sort(Comparator.comparingInt(v -> v));
        ListNode loop2 = head;
        for(int i=0; i<list.size(); i++) {
            loop2.val = list.get(i);
            loop2 = loop2.next;
        }

        return head;
    }
}