狂人C指针 练习题

   一个旅行社要从n个旅客中选出一名旅客，为他提供免费的环球旅行服务。旅行社安排这些旅客围成一个圆圈，从帽子中取出一张纸条，用上面写的正整数m(<n)作为报数值。游戏进行时，从第一个人开始按顺时针方向自1开始顺序报数，报到m时停止报数，报m的人被淘汰出列，然后从他顺时针方向上的下一个人开始重新报数，如此下去，直到圆圈中只剩下一个人，这个最后的幸存者就是游戏的胜利者，将得到免费旅行的奖励。

代码如下：

 1 typedef struct _node
 2 {
 3     int number;
 4     _node *pNext;
 5 }node;
 6 
 7 node *pHead = NULL;
 8 node *pTear = NULL;
 9 #define N 8
10 #define M 3
11 int main() {
12     node* pNode = NULL;
13     for (int i = 1; i <= N ; ++i)
14     {
15         pNode = (node*)malloc(sizeof(_node));
16         pNode->number = i;
17         pNode->pNext = NULL;
18         if (i == 1)
19         {
20             pHead = pNode;
21             pTear = pNode;
22             pTear->pNext = pHead;
23         }
24         else
25         {
26             pTear->pNext = pNode;
27             pTear = pNode;
28             pTear->pNext = pHead;
29         }
30     }
31 
32     node* pPre = pTear;
33     node* pNext = pHead;
34     int sum = 0;
35     pHead = NULL;
36     pTear = NULL;
37     while(pPre->pNext != pPre)
38     {
39         pNext = pPre->pNext;
40         ++sum;
41         if (sum == M)
42         {
43             if (pHead == NULL)
44             {
45                 pHead = pPre->pNext;
46                 pTear = pPre->pNext;
47             }
48             else
49             {
50                 pTear->pNext = pPre->pNext;
51                 pTear = pPre->pNext;
52             }
53             pPre->pNext = pNext->pNext;
54             sum = 0;
55             continue;
56         }
57         pPre = pPre->pNext;
58     }
59     pTear->pNext = NULL;
60     printf("%d\n",pPre->number);
61     node* p = pHead;
62     while(p != NULL)
63     {
64         printf("%d\n",p->number);
65         p = p->pNext;
66     }
67         return 0;
68 }