Poj 2356 pigeon cage principles

(It should be noted that the code I wrote outputs the result when there is an answer, but OJ also reads the result from the file, so at first glance, it seems that there is a result when I have not entered it, but I don't know about OJ. In fact, I directly use the poj3370 code AC, 32 MS, and O (?_ =) O) to directly paste the code.

#include<cstdio>  #include<cstring>  using namespace std;  #define N 100002    int sum[N],pos[N],a[N];    int main()  {        int n,i,r,t,j;        while(~scanf("%d",&n))      {          memset(pos,-1,sizeof(pos));          bool flag=false;            scanf("%d",&sum[0]);          a[0]=sum[0];          sum[0]%=n;          pos[sum[0]]=0;          if(sum[0]==0)          {              printf("1\n%d\n",sum[0]);              flag=1;          }            for(i=1;i<n;i++)          {              scanf("%d",&sum[i]);              if(flag)continue;              a[i]=sum[i];              sum[i]%=n;              sum[i]+=sum[i-1];              sum[i]%=n;              if(sum[i]==0)              {                  printf("%d\n",i+1);                  for(j=0;j<=i;j++)                      printf("%d\n",a[j]);                  flag=1;                  continue;              }              if(pos[sum[i]]==-1)pos[sum[i]]=i;              else              {                  printf("%d\n",i-pos[sum[i]]);                  for(j=pos[sum[i]]+1;j<=i;j++)                      printf("%d\n",a[j]);                  flag=1;              }          }        }        return 0;  }