/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode * insertionSortList(ListNode* head) {
        ListNode *dummy=new ListNode();
        
        while(head!=NULL){
            ListNode *next=head->next;
            head->next=NULL;
            
            ListNode *pre=dummy;
            ListNode *cur=dummy->next;
            while(cur!=NULL){
                if(head->val<cur->val){
                    break;
                }
                pre=cur;
                cur=cur->next;
            }
            pre->next=head;
            head->next=cur;
            
            head=next;
        }
        
        return dummy->next;
    }
};