#include
    
     using namespace std;// 定义链表节点class ListNode{public:    int val;    ListNode *next;    ListNode(int val)    {        this->val = val;        this->next = NULL;    }};class Solution{public:    /**    参数head是链表的第一个节点    返回值是链表的头节点    */    ListNode *insertSortList(ListNode *head)    {        ListNode *dummy = new ListNode(0); //创建一个值为0的节点        ListNode *cur = head;          while (cur != NULL)        {            ListNode *pre = dummy;              //当创建的节点的下一节点不为空，且下一节点的值小于当前节点的值            while (pre->next != NULL && pre->next->val < cur->val)             {                pre = pre->next; //将下一节点的值赋值给当前节点            }            ListNode *temp = cur->next;             cur->next = pre->next;            pre->next = cur;            cur = temp;        }        return dummy->next;    }};