二次联通门 : 

 

 

 

 

 

/*    LibreOJ #6220. sum    对所有数做一个前缀和    如果某一位模N等于另一位    则他们中间的一段的和一定为N的倍数    自己感悟一下    (MMP 我交了11遍才过！！！！⑨快把我冻成冰块！！)*/#include 
     
      #include 
      
       #define Max 1111111int pos[Max];typedef long long LL;inline void read (LL &now){    register char c = getchar ();    for (now = 0; !isdigit (c); c = getchar ());    for (; isdigit (c); now = now * 10 + c - '0', c = getchar ());}LL a[Max];int Main (){    int N; int s = 0; scanf ("%d", &N); register int i;    for (i = 1, pos[0] = 1; i <= N; ++ i)    {        read (a[i]); s = (s + a[i]) % N;            if (!pos[s]) pos[s] = i + 1;        else        {            for (register int j = pos[s]; j <= i; ++ j)                printf ("%d %lld\n", j, a[j]);            return 0;        }        }        return 0;}int ZlycerQan = Main ();int main (int argc, char *argv[]) {;}