面试必刷TOP101：12、单链表的排序

一、题目

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;
        }
        ListNode cur = head;
        List<Integer> list = new ArrayList<>();
        while(cur != null){
            list.add(cur.val);
            cur = cur.next;
        }
        Collections.sort(list);
        //int[] arr = list.stream().mapToInt(Integer::valueOf).toArray();
        ListNode result = new ListNode(-1);
        ListNode node = result;
        
        for(int i = 0;i<list.size();i++){
            node.next = new ListNode(list.get(i));
            node = node.next;
            
        }
        return result.next;
    }
}