LinkedList-147-Insertion Sort List

class Solution {
public ListNode insertionSortList(ListNode head) {
if(head == null) return null;
ListNode cur = head;
ListNode result = new ListNode(0);
ListNode helper = result;
ListNode next = null;
while(cur != null){
next = cur.next;
if(helper.next == null || helper.next.val > cur.val) helper = result;
while(helper.next != null && helper.next.val <cur.val) helper = helper.next;
cur.next = helper.next;
helper.next = cur;
cur = next;
}
return result.next;
}
}