#1101 [填空题]链表的排序

/** #1101 [填空题]链表的排序
下面程序，先创建一个链表（链表中各结点未按学号由小到大排序），然后调用sort函数，将链表中各结点按学号由小到大排序。
输入样例

3 （the 1st linked list, 2 students）
1 （code of no.1 student）
98 （score of no.1 student）
7 （code of no.2 student）
99 （score of no.2 student）
5 （code of no.3 student）
87 （score of no.3 student）


输出样例

1 98
7 99
5 87
1 98
5 87
7 99
//*/

#include "stdio.h"
#include "malloc.h"
#define LEN sizeof(struct student)

struct student
{
long num;
int score;
struct student *next;
};

struct student *create(int n)
{
struct student *head=NULL,*p1=NULL,*p2=NULL;
int i;
for(i=1;i<=n;i++)
{ p1=(struct student *)malloc(LEN);
scanf("%ld",&p1->num);
scanf("%d",&p1->score);
p1->next=NULL;
if(i==1) head=p1;
else p2->next=p1;
p2=p1;
}
return(head);
}

void print(struct student *head)
{
struct student *p;
p=head;
while(p!=NULL)
{
printf("%8ld%8d",p->num,p->score);
p=p->next;
printf("\n");
}
}

struct student *insert(struct student *head, struct student *stud)
{ struct student *p0,*p1,*p2;
p1=head; p0=stud;
if(head==NULL)
{head=p0;}
else
{ while( (p0->num > p1->num) && (p1->next!=NULL) )
{ p2=p1; p1=p1->next;}
if( p0->num < p1->num )
{ if( head==p1 ) head=p0;
else p2->next=p0;
p0->next=p1; }
else { p1->next=p0;}
}
return(head);
}

struct student *del(struct student *head,long num)
{
struct student *p1,*p2;
p1=head;
while(p1!=NULL)
{
if(p1->num == num)
{
if(p1 == head) head=p1->next;
else p2->next=p1->next;
free(p1);
break;
}
p2=p1;
p1=p1->next;
}
return(head);
}

struct student *sort(struct student *head)
{
struct student *sort_head=NULL, *p=NULL;
if(head==NULL || head->next==NULL)return head;
while(head){
p=head;
head = head -> next;
p->next = NULL;
sort_head = insert(sort_head, p);
}
return sort_head;
}

main()
{
struct student *head,*stu;
int n;
scanf("%d",&n);
head=create(n);
print(head);
head=sort(head);
print(head);
}