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class Solution {
public:
    int GetCount(ListNode *head) {
        int count = 0;
        while(head != NULL) {
            count++;
            head=head->next;
        }
        return count;
    }
    ListNode *insertionSortList(ListNode *head) {
        if(head == NULL)return head;
        ListNode * now = head->next;
        ListNode * before = head;
        int count = GetCount(head);
        while(now != NULL) {
            ListNode * tmpnow = now->next;
            if(now->val <= head->val) {
                ListNode * tmp = now->next;
                before->next = now->next;
                now->next = head;
                head = now;
                now = tmpnow;
            }
            else {
                ListNode * beforetmp = head;
                ListNode * tmp = beforetmp->next;
                while(tmp != now && tmp->val <= now->val) {
                    beforetmp = beforetmp->next;
                    tmp = tmp->next;
                } 
                if(tmp != now) {
                    beforetmp->next = now;
                    before->next = now->next;
                    now->next = tmp;
                    now = tmpnow;
                }
                else {
                    before = now;
                    now = tmpnow;
                }
            }
        }
        ListNode * chead = head;
        for(int i = 1;i < count;i++) {
            chead = chead->next;
        }
        chead->next = NULL;
        return head;
    }
};