/in/foo.cc: In function 'int main()':
/in/foo.cc:16:26: warning: use of 'll' length modifier with 'f' type character has either no effect or undefined behavior [-Wformat=]
    scanf("%llf", &a[i][j]);
                          ^
/in/foo.cc:77:50: warning: use of 'll' length modifier with 'f' type character has either no effect or undefined behavior [-Wformat=]
  for(int i=1; i<=n; i++) printf("%.3llf ", ans[i]);
                                                  ^