约瑟夫问题（n个人围圈报数，报m出列，最后剩下的是几号？）

//n个人围圈报数，报m出列，最后剩下的是几号？
#include <stdio.h>
#include <stdlib.h>

typedef struct node
{
int data;
struct node *next;
}node;

node *create(int n)
{
node *p = NULL, *head;
head = (node*)malloc(sizeof (node ));
p = head;
node *s;
int i = 1;

if( 0 != n )
{
while( i <= n )
{
s = (node *)malloc(sizeof (node));
s->data = i++;    // 为循环链表初始化，第一个结点为1，第二个结点为2。
p->next = s;
p = s;
}
s->next = head->next;
}

free(head);

return s->next ;
}

int main()
{
int n = 41;
int m = 3;
int i;
node *p = create(n);
node *temp;

m %= n;   // m在这里是等于3

while (p != p->next )
{
for (i = 1; i < m-1; i++)
{
p = p->next ;
}

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

temp = p->next ;                //删除第m个节点
p->next = temp->next ;
free(temp);

p = p->next ;
}

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

return 0;
}

/*编号为1～N的N个人按顺时针方向围坐一圈，每人持有一个密码（正整数，可以自由输入），
开始人选一个正整数作为报数上限值M，从第一个人按顺时针方向自1开始顺序报数，报道M时停止报数。
报M的人出列，将他的密码作为新的M值，从他顺时针方向上的下一个人开始从1报数，如此下去，直至所有人全部出列为止。*/
#include <stdio.h>
#include <stdlib.h>
#define MAX_NODE_NUM 100
#define TRUE 1U
#define FALSE 0U

typedef struct NodeType
{
int id;
int cipher;
struct NodeType *next;
} NodeType;

/* 创建单向循环链表 */
static void CreaList(NodeType **, const int);
/* 运行"约瑟夫环"问题 */
static void StatGame(NodeType **, int);
/* 打印循环链表 */
static void PrntList(const NodeType *);
/* 得到一个结点 */
static NodeType *GetNode(const int, const int);
/* 测试链表是否为空, 空为TRUE，非空为FALSE */
static unsigned EmptyList(const NodeType *);

int main(void)
{
int n, m;
NodeType *pHead = NULL;
while (1)
{
printf("请输入人数n（最多%d个）: ", MAX_NODE_NUM);
scanf("%d", &n);
printf("和初始密码m: ");
scanf("%d", &m);
if (n > MAX_NODE_NUM)
{
printf("人数太多，请重新输入！\n");
continue;
}
else
break;
}
CreaList(&pHead, n);
printf("\n------------ 循环链表原始打印 -------------\n");
PrntList(pHead);
printf("\n-------------删除出队情况打印 -------------\n");
StatGame(&pHead, m);
}

static void CreaList(NodeType **ppHead, const int n)
{
int i, iCipher;
NodeType *pNew, *pCur;
for (i = 1; i <= n; i++)
{
printf("输入第%d个人的密码: ", i);
scanf("%d", &iCipher);
pNew = GetNode(i, iCipher);
if (*ppHead == NULL)
{
*ppHead = pCur = pNew;
pCur->next = *ppHead;
}
else
{
pNew->next = pCur->next;
pCur->next = pNew;
pCur = pNew;
}
}
printf("完成单向循环链表的创建!\n");
}

static void StatGame(NodeType **ppHead, int iCipher)
{
int iCounter, iFlag = 1;
NodeType *pPrv, *pCur, *pDel;
pPrv = pCur = *ppHead;
/* 将pPrv初始为指向尾结点，为删除作好准备 */
while (pPrv->next != *ppHead)
pPrv = pPrv->next;
while (iFlag)
{
for (iCounter = 1; iCounter < iCipher; iCounter++)
{
pPrv = pCur;
pCur = pCur->next;
}
if (pPrv == pCur)
iFlag = 0;
pDel = pCur; /* 删除pCur指向的结点，即有人出列 */
pPrv->next = pCur->next;
pCur = pCur->next;
iCipher = pDel->cipher;
printf("第%d个人出列, 密码: %d\n", pDel->id, pDel->cipher);
free(pDel);
}
*ppHead = NULL;
getchar();
}

static void PrntList(const NodeType *pHead)
{
const NodeType *pCur = pHead;
if (EmptyList(pHead))
return;
do
{
printf("第%d个人, 密码: %d\n", pCur->id, pCur->cipher);
pCur = pCur->next;
}
while (pCur != pHead);
getchar();
}

static NodeType *GetNode(const int iId, const int iCipher)
{
NodeType *pNew;
pNew = (NodeType *)malloc(sizeof(NodeType));
if(!pNew)
{
printf("Error, the memory is not enough!\n");
exit(-1);
}
pNew->id = iId;
pNew->cipher = iCipher;
pNew->next = NULL;
return pNew;
}

static unsigned EmptyList(const NodeType *pHead)
{
if(!pHead)
{
printf("The list is empty!\n");
return TRUE;
}
return FALSE;
}