POJ 2359 Questions(约瑟夫环)

#include<stdio.h>
const int maxn=30000+10;
char s[maxn];
int main()
{
char ch;
int k=0;
int m=1999,pos=0;
while((ch=getchar())!=EOF){
if(ch!='\n')
s[k++]=ch;
}
for(int i=2;i<=k;i++) pos=(pos+m)%i;
if(s[pos]=='?') printf("Yes\n");
else if(s[pos]==' ') printf("No\n");
else printf("No comments\n");
}