poj 3370 Halloween treats

#include<stdio.h>#include<string.h>#define N 100010int main(){ int a[N],b[N],n,m,i,s,begin,end; while(scanf("%d%d",&n,&m)&&n+m) {  memset(b,0,sizeof(b));  for(i=1;i<=m;i++)  scanf("%d",&a[i]);  begin=end=0;  for(s=0,i=1;i<=n;i++)  {   s=(s+a[i])%n;   if(s==0){    begin=1;    end=i;    break;   }   if(!b[s]) b[s]=i;   else{    begin=b[s]+1;    end=i;    break;   }  }  for(i=begin;i<=end;i++)   if(i==end) printf("%d\n",i);   else printf("%d ",i); } return 0;}