给排序添加一个判断为空或只有一个元素 添完就无法运行..有没有大佬看一下

#include <stdio.h>

#include <stdlib.h>

#include <malloc.h>

#include <time.h>

#include <locale.h>



typedef struct Node

{

    int data;

    struct Node *next;

}LNode, *LinkList;



void QuickSort2(LinkList head, LinkList tail){

	if(head == tail)             //如果头指针为空或者链表为空，直接返回

		return ;

	//if (head->next == tail || head->next->next == tail)

         //return;

	int t;

	LinkList p = head -> next;                 

	LinkList small = head;

	while( p != tail){

		if(p -> data < head -> data){     

			small = small -> next;

			t = small -> data;

			small -> data = p -> data;

			p -> data = t;



		}

		p = p -> next;

	}

	t = head -> data;                           

	head -> data = small -> data;

	small -> data = t;

	

	QuickSort2(head, small);                     

	QuickSort2(small -> next, tail);

}



void create_list(LinkList *L) {

    int i;

    int n;

    LinkList head,p,q; 



    *L = ( struct Node *)malloc(sizeof(LNode));

    p = *L;

	head = NULL;

    p->data = -1;

    p->next = NULL;



    printf("请输入您需要生成的结点个数：");

    scanf("%d", &n);

    

    for(i = 0; i < n; i++) {

        

        q=(struct Node *)malloc(sizeof(LNode));

		if (NULL==q) exit(1);

		q->data=rand()%100;

		q->next=NULL;

		if (NULL==p) {

            head=q;

            p=head;

        } else {

            p->next=q;

            p=q;

		

    }



}}





void traverse_list(LinkList L) {

    LinkList p = L->next;



    while(NULL != p) {

        printf("%d ", p->data);

        p = p->next;

    }

    printf("\n");

    return;

}



main(){

	LinkList La = NULL;

	clock_t start, finish;

    double  duration;

    

    create_list(&La);

    //printf("排序前：\n");

    traverse_list(La);

    //InitList(&La);

    //start=clock();

    

    QuickSort2(La,NULL);

    

    //finish=clock();

     

    //printf("排序后：\n");

    traverse_list(La);

    

    //duration = (double)(finish - start) / CLOCKS_PER_SEC;

	//printf( "%f seconds\n", duration );



	return 0;

}