注意新的list跟原来的list是不相连的，然后把各个状态的点记录好就行：

public ListNode insertionSortList(ListNode head) {        if (head == null || head.next == null) return head;                //We started a new list here, not the original one        ListNode dummy = new ListNode(0);        ListNode curt = head, prev = dummy, next = head;        while (curt != null) {            next = curt.next;                        while (prev.next != null && prev.next.val < curt.val) {                prev = prev.next;            }                        curt.next = prev.next;            prev.next = curt;            curt = next;            prev = dummy;        }                return dummy.next;    }