for (int j = 0; j < m; ++j) {
  int first = -1, last = -1;
  for (int i = 0; i < n; ++i) 
    if (a[i][j] == 0) {
      first = i;
      break;
    }
  for (int i = n - 1; i > 0; --i) 
    if (a[i][j] == 0) {
      last = i;
      break;
    }
  if (first < 0 ) {
    cout << j << " ... ";
    s[j] = -1
  }
  int num = 0;
  for (int i = first + 1; i  < last; ++i)
    num += a[i][j] > 0;
  s[j] = num;
}