链表的插入排序

链接：https://www.nowcoder.com/questionTerminal/152bc6c5b14149e49bf5d8c46f53152b
来源：牛客网

public class Solution {
    public ListNode insertionSortList(ListNode head) {
        if(head==null||head.next==null)
            return head;
        ListNode cursors = head;
        ListNode tempCur = null;
        ListNode temp = head;//待排序元素的上一元素
        ListNode current = temp.next;//待排序的元素
        while(current!=null){
            if(current.val<head.val){
                //排序的元素比头小 把当前元素当做头
                temp.next = current.next;
                current.next = head;
                head = current;
            }else{
                //     cursors-↓    ↓-temp
                //   1 -> 3 -> 5 -> 8 -> 4-> 12 -> 2
                //tempCur-↑      current-↑
                //插入后：
                //  |-------有序---------|
                //  1 -> 3 -> 4 -> 5 -> 8-> 12 -> 2
                //找到插入的位置 current插入到cursors的前面：temp->current->cursors
                tempCur = cursors;
                cursors = tempCur.next;
                while(cursors!=current&&cursors.val<current.val){
                    tempCur = cursors;
                    cursors = cursors.next;
                }
                if(cursors==current){
                    temp = current;
                    current = temp.next;
                }else{
                    temp.next = current.next;
                    tempCur.next = current;
                    current.next = cursors;
                }
                 
            }
            cursors = head;
            current = temp.next;
        }
        return head;
    }
}