Language: C++

#include<bits/stdc++.h>

using namespace std;
using Graph = vector<vector<int>>;

int main(){
  int N,M;
  cin >> N >> M;
  vector<int> v;

  for(int i = 0; i < N; i++){
    v.push_back(i);
  }

  for(int i = 0; i < M; i++){
    int a,b;
    cin >> a >> b;
    a--;
    b--;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  int cnt = 0;
  do{
    for(int i = 0; i < N; i++){
      if(i == N - 1) cnt++;
      else if(count(G[v[i]].begin(),G[v[i]],end(),v[i + 1]) == 0){
        break;
      }
    }
  }while(next_permutation(v.begin()+1,v.end()));

  cout << cnt << endl;

  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:20:5: error: 'G' was not declared in this scope
   20 |     G[a].push_back(b);
      |     ^
a.cc:27:21: error: 'G' was not declared in this scope
   27 |       else if(count(G[v[i]].begin(),G[v[i]],end(),v[i + 1]) == 0){
      |                     ^
a.cc:27:48: error: no matching function for call to 'end()'
   27 |       else if(count(G[v[i]].begin(),G[v[i]],end(),v[i + 1]) == 0){
      |                                             ~~~^~
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: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
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: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
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/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