C语言约瑟夫环链表

#include <stdio.h>

#include <windows.h>

#include <string.h>

struct link * creat1(int n);

void out(struct link * head);

void free_(struct link * head);

struct link * jsf(struct link * head,int m);

struct link

{
int data;
struct link * next;

};

void main()

{

    struct link * head;
struct link * p;
int n,m;
printf("input n , m:");  //读入个数与约定删除数
scanf("%d %d",&n,&m);
head = creat1(n);
out(head);
p = jsf(head,m);
printf("\nlast: %d \n",p->data);
free(p);

}

struct link * jsf(struct link * head,int m)

{

    int i;
struct link * p = malloc(sizeof(struct link ));    //给无头结点链表添加辅助头结点，但循环链表的尾巴仍指向第一个元素点，而不是头结点

    struct link * q;
p->next = head;
head = p;
while(p->next != p) //只剩下一个节点时，即为结果
{
for(i = 0; i < m; i++)  //数到M删除一次
{
q = p;
p = p->next;
}
q->next = p->next;
free(p);
p = q;
}
free(head);//删除头结点

    return p;

}

struct link * creat1(int n)    //创建循环链表

{

    struct link * head;

    struct link * p;
struct link * q;

    int i = 1;
head = (struct link *)malloc(sizeof(struct link));
p = q = (struct link *)malloc(sizeof(struct link));

    p->data = i;
head->next=p;
while (i < n)
{
i++;
p = (struct link *)malloc(sizeof(struct link));
p->data = i;
q->next = p;
q = p;
}
p = head->next;   //删除头结点。使之为无头结点链表，多此一举，懒得改

    q->next = p;
free(head);
return p;

}

void out(struct link * head)  //输出无头结点链表

{

    struct link * p = head->next;

    printf("%d ",head->data);
while(p != head)
{
printf("%d ",p->data);
p = p->next;
}
putchar(10);

}

void free_(struct link * head)   //删除无头结点链表，未使用

{

    struct link * p = head->next;
struct link * q = head;
while(head != p)
{
q = p->next;

        free(p);
p = q;
}

    free(head);

}