Language: C++

#include<bits/stdc++.h>
#define rp(i,n) for(int i=0; i<n;i++)
using namespace std;
using Graph = vector <vector<int>>;

vector<bool> seen(n+1,false);
void dfs(const Graph &G,int v,int ctr,Graph& tree){
  seen.at(v) = true;
  tree[ctr].push_back(v)
  for(auto next_v:G.at(v)){
    if(seen.at(next_v)) continue;
    dfs(G,next_v,ctr,tree);
  }
}

int main(){
  int n,m,k;
  cin >> n >> m >> k;
  
  Graph friends(n+1);
  rp(i,m){
    int a,b;
    cin >> a >> b;
    friends[a].push_back(b);
    friends[b].push_back(a);
  }
  
  int tree_ctr=0;
  Graph friendstree;
  for(int i=1; i<=n;i++){
    if(!seen.at(i)){
      dfs(friends,i,tree_ctr,friendstree);
      tree_ctr++;
    }
  }
  
  vector<int> answer(n+1);
  for(int i=0; i<friendstree.size(); i++){
    for(int j=0; j<friendstree.at(i).size(); j++){
      answer(friendstree.at(i).at(j))
        =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
    }
  }
  
  rp(i,k){
    int c,d;
    cin >> c >> d;
    int ctree,dtree;
    bool cok=false;
    bool dok=false;
    bool escape=false;
    rp(j,freindstree.size()){
      rp(l,friendstree.at(j).size()){
        if(c==friendstree.at(j).at(l)){
          ctree=j;
          cok=true;
        }
        if(d==friendstree.at(j).at(l)){
          dtree=j;
          dok=true;
        }
        if(cok&&dok){
          escape=true;
          break;
        }
      }
      if(escape)
        break;
    }
    if(ctree==dtree){
      answer.at(c)--;
      answer.at(d)--;
    }
  }
  for(int i=1; i<=n; i++)
    cout << answer.at(i) << endl;
  
  return 0;
}
        
    
  

Compiler output:
a.cc:6:19: error: 'n' was not declared in this scope; did you mean 'yn'?
    6 | vector<bool> seen(n+1,false);
      |                   ^
      |                   yn
a.cc: In function 'void dfs(const Graph&, int, int, Graph&)':
a.cc:9:25: error: expected ';' before 'for'
    9 |   tree[ctr].push_back(v)
      |                         ^
      |                         ;
   10 |   for(auto next_v:G.at(v)){
      |   ~~~                    
a.cc: In function 'int main()':
a.cc:40:13: error: no match for call to '(std::vector<int>) (__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type&)'
   40 |       answer(friendstree.at(i).at(j))
      |       ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:41:34: error: no match for 'operator-' (operand types are 'std::vector<int>::size_type' {aka 'long unsigned int'} and '__gnu_cxx::__alloc_traits<std::allocator<std::vector<int> >, std::vector<int> >::value_type' {aka 'std::vector<int>'})
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |          ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                                |            |
      |                                |            __gnu_cxx::__alloc_traits<std::allocator<std::vector<int> >, std::vector<int> >::value_type {aka std::vector<int>}
      |                                std::vector<int>::size_type {aka long unsigned int}
In file included from /usr/include/c++/14/bits/stl_algobase.h:67,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:618:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr decltype ((__y.base() - __x.base())) std::operator-(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  618 |     operator-(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:618:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'std::vector<int>::size_type' {aka 'long unsigned int'}
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/bits/stl_iterator.h:1790:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr decltype ((__x.base() - __y.base())) std::operator-(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1790 |     operator-(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1790:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'std::vector<int>::size_type' {aka 'long unsigned int'}
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
In file included from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/complex:370:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&, const complex<_Tp>&)'
  370 |     operator-(const complex<_Tp>& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:370:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   mismatched types 'const std::complex<_Tp>' and 'std::vector<int>::size_type' {aka 'long unsigned int'}
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/complex:379:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&, const _Tp&)'
  379 |     operator-(const complex<_Tp>& __x, const _Tp& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:379:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   mismatched types 'const std::complex<_Tp>' and 'std::vector<int>::size_type' {aka 'long unsigned int'}
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/complex:388:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const _Tp&, const complex<_Tp>&)'
  388 |     operator-(const _Tp& __x, const complex<_Tp>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/complex:388:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::vector<int> >, std::vector<int> >::value_type' {aka 'std::vector<int>'} is not derived from 'const std::complex<_Tp>'
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/complex:465:5: note: candidate: 'template<class _Tp> std::complex<_Tp> std::operator-(const complex<_Tp>&)'
  465 |     operator-(const complex<_Tp>& __x)
      |     ^~~~~~~~
/usr/include/c++/14/complex:465:5: note:   candidate expects 1 argument, 2 provided
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'std::vector<int>::size_type' {aka 'long unsigned int'}
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'std::vector<int>::size_type' {aka 'long unsigned int'}
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::vector<int> >, std::vector<int> >::value_type' {aka 'std::vector<int>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'std::vector<int>::size_type' {aka 'long unsigned int'}
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/bits/valarray_after.h:406:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__minus, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__minus, typename _Dom1::value_type>::result_type> std::operator-(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  406 |     _DEFINE_EXPR_BINARY_OPERATOR(-, struct std::__minus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:406:5: note:   template argument deduction/substitution failed:
a.cc:41:69: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::vector<int> >, std::vector<int> >::value_type' {aka 'std::vector<int>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   41 |         =friendstree.at(i).size()-friends.at(friendstree.at(i).at(j))-1;
      |                                                                     ^
/usr/include/c++/14/valarray:1197:1: note: candidate: 'template<class _Tp> std::_Expr<std::__det