foo.cc: In function 'int main()':
foo.cc:14:46: error: invalid types 'long long int[long long int]' for array subscript
  for(i=1;i<=10;i++)scanf("%lld %lld",&a[i*2-1],&a[i*2]);
                                              ^
foo.cc:14:54: error: invalid types 'long long int[long long int]' for array subscript
  for(i=1;i<=10;i++)scanf("%lld %lld",&a[i*2-1],&a[i*2]);
                                                      ^
foo.cc:15:35: warning: format '%lld' expects a matching 'long long int' argument [-Wformat=]
  printf("%lld\n%lld%lld%lld",n,a,b);
                                   ^
foo.cc:9:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld %lld",&n,&m);
  ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:10:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld %lld %lld",&a,&b,&c);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:11:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld %lld %lld",&a,&b,&c);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:12:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld %lld %lld",&a,&b,&c);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:13:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld %lld %lld",&a,&b,&c);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

自豪的采用 HydroJudge 进行评测(github.com/hydro-dev/HydroJudge)