Language: C++

#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;

int N, M;
int A[100000];
vector<int> G[100000];
bool used[100000];
multiset<int> ms[100000];

void DFS(int from, int prev, int start) {
  used[from] = true;
  ms[start].insert(A[from]);
  for(int to : G[from]){
    if (to == prev || used[to]) continue;
    DFS(to, from, start);
  }
}

int main() {
  cin >> N >> M;
  if (M + 1 == N) {
    cout << 0 << endl;
    return 0;
  }
  
  for (int i = 0; i < N; ++i) {
    cin >> A[i];
  }
  for (int i = 0; i < M; ++i) {
    int a, b;
    cin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  
  vector<int> tr;
  for (int i = 0; i < N; ++i) {
    if (used[i]) continue;
    tr.push_back(i);
    DFS(i, -1, i);
  }
  
  long long sum = 0;
  vector<int> v;
  for (int i = 0; i < tr.size(); ++i) {
    multiset<int>& z = ms[tr[i]];
    sum += *z.begin();
    for (auto it = next(z.begin()); it != tr.end(); ++it) {
      v.push_back(*it);
    }
  }
  
  sort(v.begin(), v.end());
  if(v.size() < tr.size() - 2) {
    cout << "Impossible" << endl;
    return 0;
  }
  
  for(int i = 0; i < tr.size() - 2; ++i) {
    sum += v[i];
  }
  cout << sum << endl;
  
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:51:40: error: no match for 'operator!=' (operand types are 'std::_Rb_tree_const_iterator<int>' and 'std::vector<int>::iterator')
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                     ~~ ^~ ~~~~~~~~
      |                                     |           |
      |                                     |           std::vector<int>::iterator
      |                                     std::_Rb_tree_const_iterator<int>
In file included from /usr/include/c++/14/iosfwd:42,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/postypes.h:197:5: note: candidate: 'template<class _StateT> bool std::operator!=(const fpos<_StateT>&, const fpos<_StateT>&)'
  197 |     operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:197:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::fpos<_StateT>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
In file included from /usr/include/c++/14/string:43,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44:
/usr/include/c++/14/bits/allocator.h:243:5: note: candidate: 'template<class _T1, class _T2> bool std::operator!=(const allocator<_CharT>&, const allocator<_T2>&)'
  243 |     operator!=(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:243:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::allocator<_CharT>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
In file included from /usr/include/c++/14/string:48:
/usr/include/c++/14/bits/stl_iterator.h:455:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  455 |     operator!=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:455:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/bits/stl_iterator.h:500:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  500 |     operator!=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:500:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1686 |     operator!=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::move_iterator<_IteratorL>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1753 |     operator!=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::move_iterator<_IteratorL>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/stl_pair.h:1052:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator!=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1052 |     operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1052:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::pair<_T1, _T2>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:651:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  651 |     operator!=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:651:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/string_view:658:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  658 |     operator!=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:658:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/string_view:666:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  666 |     operator!=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:666:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   '__gnu_cxx::__normal_iterator<int*, std::vector<int> >' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/bits/basic_string.h:3833:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator!=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3833 |     operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3833:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/bits/basic_string.h:3847:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator!=(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3847 |     operator!=(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3847:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   mismatched types 'const _CharT*' and 'std::_Rb_tree_const_iterator<int>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
/usr/include/c++/14/bits/basic_string.h:3860:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator!=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3860 |     operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3860:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |                                                  ^
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2613:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator!=(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2613 |     operator!=(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2613:5: note:   template argument deduction/substitution failed:
a.cc:51:50: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::tuple<_UTypes ...>'
   51 |     for (auto it = next(z.begin()); it != tr.end(); ++it) {
      |