Language: C++

#include<iostream>
#include<set>
#include<algorithm>
//#include<numeric>
using namespace std;

int main(){
  int N;
  cin >> N;
  multiset<int>max;
  for(int i=1; i<=N; i++) {
    int M;
    cin >> M;
    for(int j=1; j<=M; j++) {
      int c;
      cin >> c;
      max.insert(c);
      if(max.size() > i) max.erase(max.begin());
    }
  }
  //cout << accumulate(max.cbegin(), max.cend(), 0) << endl;
  unsigned long long ans = 0;
  for(auto it=max.begin(); it<max.end(); it++) ans += it;
  cout << ans << endl;
}




Compiler output:
a.cc: In function 'int main()':
a.cc:23:30: error: no match for 'operator<' (operand types are 'std::_Rb_tree_const_iterator<int>' and 'std::multiset<int>::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::less<int>, std::allocator<int> >::const_iterator'})
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                            ~~^~~~~~~~~~
      |                            |         |
      |                            |         _Rb_tree_const_iterator<[...]>
      |                            _Rb_tree_const_iterator<[...]>
In file included from /usr/include/c++/14/string:48,
                 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,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:448:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  448 |     operator<(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:448:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/bits/stl_iterator.h:493:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  493 |     operator<(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:493:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::reverse_iterator<_Iterator>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/bits/stl_iterator.h:1694:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1694 |     operator<(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1694:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::move_iterator<_IteratorL>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/bits/stl_iterator.h:1760:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1760 |     operator<(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1760:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::move_iterator<_IteratorL>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += 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:1045:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator<(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1045 |     operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1045:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::pair<_T1, _T2>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += 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:673:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  673 |     operator< (basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:673:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/string_view:680:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  680 |     operator< (basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:680:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/string_view:688:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  688 |     operator< (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:688:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/bits/basic_string.h:3874:5: 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>&)'
 3874 |     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3874:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/bits/basic_string.h:3888:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3888 |     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3888:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
/usr/include/c++/14/bits/basic_string.h:3901:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3901 |     operator<(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3901:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   mismatched types 'const _CharT*' and 'std::_Rb_tree_const_iterator<int>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += 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:2600:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator<(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2600 |     operator<(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2600:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::tuple<_UTypes ...>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
In file included from /usr/include/c++/14/set:63,
                 from a.cc:2:
/usr/include/c++/14/bits/stl_set.h:1025:5: note: candidate: 'template<class _Key, class _Compare, class _Alloc> bool std::operator<(const set<_Key, _Compare, _Allocator>&, const set<_Key, _Compare, _Allocator>&)'
 1025 |     operator<(const set<_Key, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_set.h:1025:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::set<_Key, _Compare, _Allocator>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
In file included from /usr/include/c++/14/set:64:
/usr/include/c++/14/bits/stl_multiset.h:1011:5: note: candidate: 'template<class _Key, class _Compare, class _Alloc> bool std::operator<(const multiset<_Key, _Compare, _Allocator>&, const multiset<_Key, _Compare, _Allocator>&)'
 1011 |     operator<(const multiset<_Key, _Compare, _Alloc>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_multiset.h:1011:5: note:   template argument deduction/substitution failed:
a.cc:23:39: note:   'std::_Rb_tree_const_iterator<int>' is not derived from 'const std::multiset<_Key, _Compare, _Allocator>'
   23 |   for(auto it=max.begin(); it<max.end(); it++) ans += it;
      |                                       ^
In file incl