Language: C++

#include<iostream>
#include<set>
#include<iterator>
using namespace std;
int main()
{
  int i, n, x, comfort = 0;
  multiset<int, greater<int> > s;
  multiset<int, greater<int> >::iterator it;
  cin >> n;
  
  for(i=0; i<n; i++)
  {
    cin >> x;
    if(s.empty())
    {
      s.insert(x);
      it = s.begin();
      continue;
    }
    if(s.size() == 1)
    {
      comfort += *it;
      s.insert(x);
      it = s.begin() + 1;
      continue;
    }
    if(s.size()>1)
    {
      comfort += *it;
      s.insert(x);
      it = s.begin() + 1;
      continue;
    }
  }
  cout << comfort;
  return(0);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:25:22: error: no match for 'operator+' (operand types are 'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} and 'int')
   25 |       it = s.begin() + 1;
      |            ~~~~~~~~~ ^ ~
      |                   |    |
      |                   |    int
      |                   std::multiset<int, std::greater<int> >::iterator {aka std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::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:627:5: note: candidate: 'template<class _Iterator> constexpr std::reverse_iterator<_Iterator> std::operator+(typename reverse_iterator<_Iterator>::difference_type, const reverse_iterator<_Iterator>&)'
  627 |     operator+(typename reverse_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:627:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note: candidate: 'template<class _Iterator> constexpr std::move_iterator<_IteratorL> std::operator+(typename move_iterator<_IteratorL>::difference_type, const move_iterator<_IteratorL>&)'
 1798 |     operator+(typename move_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   25 |       it = s.begin() + 1;
      |                        ^
In file included from /usr/include/c++/14/string:54:
/usr/include/c++/14/bits/basic_string.h:3598:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3598 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3598:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3616:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3616 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3616:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   mismatched types 'const _CharT*' and 'std::_Rb_tree_const_iterator<int>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3635:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3635 |     operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3635:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3652:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3652 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3652:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3670:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)'
 3670 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3670:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3682:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3682 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3682:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3689:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3689 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3689:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3696:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3696 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3696:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3719:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3719 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3719:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   mismatched types 'const _CharT*' and 'std::_Rb_tree_const_iterator<int>'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3726:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3726 |     operator+(_CharT __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3726:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   25 |       it = s.begin() + 1;
      |                        ^
/usr/include/c++/14/bits/basic_string.h:3733:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const _CharT*)'
 3733 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3733:5: note:   template argument deduction/substitution failed:
a.cc:25:24: note:   'std::multiset<int, std::greater<int> >::iterator' {aka 'std::_Rb_tree<int, int, std::_Identity<int>, std::greater<int>, std::allocator<int> >::const_iterator'} is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allo