习题3.10 约瑟夫环 josephus问题

/* assume a header */

/* 双向循环链表 */

struct Node;

typedef struct Node * PtrToNode;

typedef PtrToNode List;

typedef PtrToNode position;



struct Node{

    PtrToNode Previous;

    PtrToNode Next;

    int Ele;

};

/* 删除双向循环链表中的元素例程 */

Position

Delete( Position p )

{

    Position tmp;

    tmp = p->next;

    p->Previous->Next = tmp;

    tmp->Previous = p->Previous;

    free( p );

    return tmp;

}

void

josephus( List L, int m, int n )

{

    int i,count = 0;

    Position p;

    p = L->Next;

    while( n > 1 )

    {

        count = m % n;

        for(i = 0; i < count; i++)

            p = p->Next;

        p = Delete( p );

        n--;

    }

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

}

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L默认为双向循环链表，L为表头，Delete为删除双向链表结点的函数

整个表结构类似一个圆圈上面加一个表头

拓展：创建一个双向循环链表，以输入为0结束

struct Node{

    PtrToNode Previous;

    PtrToNode Next;

    int Ele;

};

//创建一个双向循环链表

Position

CreateDoubleList( void )

{

   PtrToNode head,last,now;

   head = last = malloc( sizeof(struct Node ) );

   now = malloc( sizeof(strut Node ) );

   scanf("%d",&now->Ele);

   while(now->Ele != 0)

   {

       last->Next = now;

       now->Previous = last;

       last = now;

       now = malloc( sizeof( struct Node ) );

       scanf("%d",&now->Ele);

   }

   last->Next = head;

   head->Previous = last;

   free(now);

   return head;

}

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创建一个单链表，类似

//创建一个单向链表



struct Node{

    int data;

    PtrToNode Next;

};

Position

CreateSingleList( void )

{

    Position head,last,now;

    head = last = malloc( sizeof( struct Node ) );

    now = malloc( sizeof( struct Node ) );

    scanf("%d",&now->data);

    while(now->data != 0)

    {

        last->Next = now;

        last = now;

        now = malloc( sizeof( struct Node ) );

        scanf("%d",&now->data);

    }

    last->Next = NULL;

    free(now);

    return head;

}

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