Language: C++

#include <bits/stdc++.h>
using namespace std;

using Graph=vector<vector<int>>;

int main(){
  int N,M,S,T;
  cin>>N>>M;
  Graph G(N);
  for(int i=0;i<M;++i){
    int u,v;
    cin>>u>>v;
    --u,--v;
    G[u].push_back(v);
  }
  cin>>S>>T;
  --S,--T;

  queue<vector<int64_t>(3)> que;
  vector<vector<bool>> ch(N,vector<int>(3));
  vector<int>(3) v={0,0,0};
  que.push(v);
  int64_t ans=0;
  bool flag=false;
  while(!que.empty()){

    auto w=que.front();
    que.pop();
    int64_t x=w[0],y=w[1],z=w[2];
    ch[u][v]=true;

    if(u==T && v==0){
      if(!flag) ans=z;
      else ans=min(ans,z);
    }
    else{
      if(y!=2){
        for(auto nv:G[v]){
          if(!ch[y+1][nv]){
            vector<int64_t> nw(3)={nv,y+1,z};
            que.push(nw);
          }
        }
      }
      if(w[2]==2){
        for(auto nv:G[v]){
          if(!ch[y+1][nv]){
            vector<int64_t> nw(3)={nv,0,z+1};
            que.push(nw);
          }
        }
      }
    }
  }

  cout<<ans<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:19:9: error: temporary of non-literal type 'std::vector<long int>' in a constant expression
   19 |   queue<vector<int64_t>(3)> que;
      |         ^~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_vector.h:428:11: note: 'std::vector<long int>' is not literal because:
  428 |     class vector : protected _Vector_base<_Tp, _Alloc>
      |           ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:428:11: note:   'std::vector<long int>' has a non-trivial destructor
a.cc:19:27: error: type/value mismatch at argument 1 in template parameter list for 'template<class _Tp, class _Sequence> class std::queue'
   19 |   queue<vector<int64_t>(3)> que;
      |                           ^
a.cc:19:27: note:   expected a type, got 'std::vector<long int>(3, std::allocator<long int>())'
a.cc:19:27: error: template argument 2 is invalid
a.cc:20:43: error: no matching function for call to 'std::vector<std::vector<bool> >::vector(int&, std::vector<int>)'
   20 |   vector<vector<bool>> ch(N,vector<int>(3));
      |                                           ^
/usr/include/c++/14/bits/stl_vector.h:707:9: note: candidate: 'template<class _InputIterator, class> std::vector<_Tp, _Alloc>::vector(_InputIterator, _InputIterator, const allocator_type&) [with <template-parameter-2-2> = _InputIterator; _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >]'
  707 |         vector(_InputIterator __first, _InputIterator __last,
      |         ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:707:9: note:   template argument deduction/substitution failed:
a.cc:20:43: note:   deduced conflicting types for parameter '_InputIterator' ('int' and 'std::vector<int>')
   20 |   vector<vector<bool>> ch(N,vector<int>(3));
      |                                           ^
/usr/include/c++/14/bits/stl_vector.h:678:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; allocator_type = std::allocator<std::vector<bool> >]'
  678 |       vector(initializer_list<value_type> __l,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:678:43: note:   no known conversion for argument 1 from 'int' to 'std::initializer_list<std::vector<bool> >'
  678 |       vector(initializer_list<value_type> __l,
      |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:659:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<bool> >]'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:659:23: note:   no known conversion for argument 1 from 'int' to 'std::vector<std::vector<bool> >&&'
  659 |       vector(vector&& __rv, const __type_identity_t<allocator_type>& __m)
      |              ~~~~~~~~~^~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::false_type) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; allocator_type = std::allocator<std::vector<bool> >; std::false_type = std::false_type]'
  640 |       vector(vector&& __rv, const allocator_type& __m, false_type)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:640:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:635:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&, const allocator_type&, std::true_type) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; allocator_type = std::allocator<std::vector<bool> >; std::true_type = std::true_type]'
  635 |       vector(vector&& __rv, const allocator_type& __m, true_type) noexcept
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:635:7: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_vector.h:624:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&, std::__type_identity_t<_Alloc>&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; std::__type_identity_t<_Alloc> = std::allocator<std::vector<bool> >]'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:624:28: note:   no known conversion for argument 1 from 'int' to 'const std::vector<std::vector<bool> >&'
  624 |       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
      |              ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(std::vector<_Tp, _Alloc>&&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >]'
  620 |       vector(vector&&) noexcept = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:620:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:601:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >]'
  601 |       vector(const vector& __x)
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:601:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:569:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const value_type&, const allocator_type&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; size_type = long unsigned int; value_type = std::vector<bool>; allocator_type = std::allocator<std::vector<bool> >]'
  569 |       vector(size_type __n, const value_type& __value,
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:569:47: note:   no known conversion for argument 2 from 'std::vector<int>' to 'const std::vector<std::vector<bool> >::value_type&' {aka 'const std::vector<bool>&'}
  569 |       vector(size_type __n, const value_type& __value,
      |                             ~~~~~~~~~~~~~~~~~~^~~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(size_type, const allocator_type&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; size_type = long unsigned int; allocator_type = std::allocator<std::vector<bool> >]'
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:556:51: note:   no known conversion for argument 2 from 'std::vector<int>' to 'const std::vector<std::vector<bool> >::allocator_type&' {aka 'const std::allocator<std::vector<bool> >&'}
  556 |       vector(size_type __n, const allocator_type& __a = allocator_type())
      |                             ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector(const allocator_type&) [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >; allocator_type = std::allocator<std::vector<bool> >]'
  542 |       vector(const allocator_type& __a) _GLIBCXX_NOEXCEPT
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:542:7: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_vector.h:531:7: note: candidate: 'std::vector<_Tp, _Alloc>::vector() [with _Tp = std::vector<bool>; _Alloc = std::allocator<std::vector<bool> >]'
  531 |       vector() = default;
      |       ^~~~~~
/usr/include/c++/14/bits/stl_vector.h:531:7: note:   candidate expects 0 arguments, 2 provided
a.cc:21:17: error: expected ';' before 'v'
   21 |   vector<int>(3) v={0,0,0};
      |                 ^~
      |                 ;
a.cc:22:7: error: request for member 'push' in 'que', which is of non-class type 'int'
   22 |   que.push(v);
      |       ^~~~
a.cc:22:12: error: 'v' was not declared in this scope
   22 |   que.push(v);
      |            ^
a.cc:25:14: error: request for member 'empty' in 'que', which is of non-class type 'int'
   25 |   while(!que.empty()){
      |              ^~~~~
a.cc:27:16: error: request for member 'front' in 'que', which is of non-class type 'int'
   27 |     auto w=que.front();
      |                ^~~~~
a.cc:28:9: error: request for member 'pop' in 'que', which is of non-class type 'int'
   28 |     que.pop();
      |         ^~~
a.cc:30:8: error: 'u' was not declared in this scope
   30 |     ch[u][v]=true;
      |        ^
a.cc:33:21: error: 'z' was not declared in this scope
   33 |       if(!flag) ans=z;
      |                     ^
a.cc:34:24: error: 'z' was not declared in this scope
   34 |       else ans=min(ans,z);
      |                        ^
a.cc:37:10: error: 'y' was not declared in this scope
   37 |       if(y!=2){
      |          ^
a.cc:40:34: error: expected ',' or ';' before '=' token
   40 |             vector<int64_t> nw(3)={nv,y+1,z};
      |                                  ^
a.cc:41:17: error: request for member 'push' in 'que', which is of non-class type 'int'
   41 |             que.push(nw);
      |                 ^~~~
a.cc:47:18: error: 'y' was not declared in this scope
   47 |           if(!ch[y+1][nv]){
      |                  ^
a.cc:48:34: error: expected ',' or ';' before '=' token
   48 |             vector<int64_t> nw(3)={nv,0,z+1};
      |                                  ^
a.cc:49:17: error: request for member 'push' in 'que', which is of non-class type 'int'
   49 |             que.push(nw);
      |                 ^~~~