poj 2356 Find a multiple

#include <cstdio>#include <cstring>int n, num[10005], prefix[10005], pre[10005];int main(){while(scanf("%d", &n) == 1){memset(pre, -1, sizeof(pre));prefix[0]=0;for(int i = 1; i <= n; i++){    scanf("%d", num + i); prefix[i] = (prefix[i - 1] + num[i])%n;    }int start, end;pre[0] = 0;for(int i = 1; i <= n; i++)    if(pre[prefix[i]] != -1){    start = pre[prefix[i]];    end = i;    break;    }    else     pre[prefix[i]] = i;printf("%dn", end - start);for(int i = start + 1; i <= end; i++) printf("%dn", num[i]);}return 0;}