给你链表的头结点 head ,请将其按 升序 排列并返回 排序后的链表 。
示例 1:
输入:head = [4,2,1,3]
输出:[1,2,3,4]
示例 2:
输入:head = [-1,5,3,4,0]
输出:[-1,0,3,4,5]
示例 3:
输入:head = []
输出:[]
提示:
链表中节点的数目在范围 [0, 5 * 104] 内
-105 <= Node.val <= 105
【解题思路】同排序8
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
class Solution {
public ListNode sortList(ListNode head) {
if(head == null) return head;
ListNode newHead = new ListNode(0, head);
ListNode sorted = head;
ListNode curr = sorted.next;
while(curr != null)
{
if(curr.val >= sorted.val)
{
sorted = sorted.next;
}
else{
ListNode pre = newHead;
while(pre.next.val <= curr.val)
{
pre = pre.next;
}
sorted.next = curr.next;
curr.next = pre.next;
pre.next = curr;
}
curr = sorted.next;
}
return newHead.next;
}
}