Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  int n;string s;cin>>n>>s;
  vector<int>r(0),g(0),b(0);
  for(int i=0;i<n;i++){
    if(s.at(i)=='R')r.push_back(i);
    else if(s.at(i)=='G')g.push_back(i);
    else b.push_back(i);
  }
  int a=r.size(),bb=g.size(),c=b.size();
  long long an=0;
  for(int i=0;i<a;i++){
    for(int j=0;j<bb;j++){
      for(int k=0;k<c;k++){
        vector<int>x(3);x.at(0)=R.at(i);x.at(1)=G.at(j);x.at(2)=B.at(k);
        x.sort(begin(),end());
        if(x.at(1)-x.at(0)!=x.at(2)-x.at(1))an++;
      }
    }
  }
  cout<<an<<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:16:33: error: 'R' was not declared in this scope
   16 |         vector<int>x(3);x.at(0)=R.at(i);x.at(1)=G.at(j);x.at(2)=B.at(k);
      |                                 ^
a.cc:16:49: error: 'G' was not declared in this scope
   16 |         vector<int>x(3);x.at(0)=R.at(i);x.at(1)=G.at(j);x.at(2)=B.at(k);
      |                                                 ^
a.cc:16:65: error: 'B' was not declared in this scope
   16 |         vector<int>x(3);x.at(0)=R.at(i);x.at(1)=G.at(j);x.at(2)=B.at(k);
      |                                                                 ^
a.cc:17:11: error: 'class std::vector<int>' has no member named 'sort'
   17 |         x.sort(begin(),end());
      |           ^~~~
a.cc:17:21: error: no matching function for call to 'begin()'
   17 |         x.sort(begin(),end());
      |                ~~~~~^~
In file included from /usr/include/c++/14/bits/algorithmfwd.h:39,
                 from /usr/include/c++/14/bits/stl_algo.h:59,
                 from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/initializer_list:88:5: note: candidate: 'template<class _Tp> constexpr const _Tp* std::begin(initializer_list<_Tp>)'
   88 |     begin(initializer_list<_Tp> __ils) noexcept
      |     ^~~~~
/usr/include/c++/14/initializer_list:88:5: note:   candidate expects 1 argument, 0 provided
In file included from /usr/include/c++/14/string:53,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/range_access.h:52:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.begin()) std::begin(_Container&)'
   52 |     begin(_Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
/usr/include/c++/14/bits/range_access.h:52:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:63:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.begin()) std::begin(const _Container&)'
   63 |     begin(const _Container& __cont) -> decltype(__cont.begin())
      |     ^~~~~
/usr/include/c++/14/bits/range_access.h:63:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:95:5: note: candidate: 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::begin(_Tp (&)[_Nm])'
   95 |     begin(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~~~
/usr/include/c++/14/bits/range_access.h:95:5: note:   candidate expects 1 argument, 0 provided
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/valarray:1227:5: note: candidate: 'template<class _Tp> _Tp* std::begin(valarray<_Tp>&)'
 1227 |     begin(valarray<_Tp>& __va) noexcept
      |     ^~~~~
/usr/include/c++/14/valarray:1227:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/valarray:1238:5: note: candidate: 'template<class _Tp> const _Tp* std::begin(const valarray<_Tp>&)'
 1238 |     begin(const valarray<_Tp>& __va) noexcept
      |     ^~~~~
/usr/include/c++/14/valarray:1238:5: note:   candidate expects 1 argument, 0 provided
a.cc:17:27: error: no matching function for call to 'end()'
   17 |         x.sort(begin(),end());
      |                        ~~~^~
/usr/include/c++/14/initializer_list:99:5: note: candidate: 'template<class _Tp> constexpr const _Tp* std::end(initializer_list<_Tp>)'
   99 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
/usr/include/c++/14/initializer_list:99:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:74:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:85:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:106:5: note: candidate: 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/valarray:1249:5: note: candidate: 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
 1249 |     end(valarray<_Tp>& __va) noexcept
      |     ^~~
/usr/include/c++/14/valarray:1249:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/valarray:1265:5: note: candidate: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
 1265 |     end(const valarray<_Tp>& __va) noexcept
      |     ^~~
/usr/include/c++/14/valarray:1265:5: note:   candidate expects 1 argument, 0 provided