有关链表的程序设计题（有木有大佬来帮忙看一下的）

#include <stdio.h>
#include <stdlib.h>
typedef struct node
{
    int id;
    struct node *next;
} node;
int main(int argc, char const *argv[])
{
    int n, i;
    scanf("%d", &n);
    node *p, *s, *r;             //head node
    p = (node *)malloc(sizeof(node));
    p->id = 1;
    p->next = NULL;
    r = p;
    for (i = 2; i <= n; ++i)   //generate a list
    {
        s = (node *)malloc(sizeof(node));
        s->id = i;
        r->next = s;
        r = r->next;
    }
    r->next = p;
    int num = 0;
    while (n > 1)     //when the number of man is 1, then exit
    {
        if (p->id != 0)
        {
            ++num;
            if (num % 3 == 0)
            {
                n -= 1;
                p->id = 0;
            }
            p = p->next;
        }
        else    p = p->next;
    }
    while (!p->id)    p = p->next;
    printf("the survivor is: %d", p->id);
    return 0;
}