Language: C++

#include <iostream>
#include <numeric>
#include <set>
using namespace std;
using uint = unsigned int;
using ull = unsigned long long;

int main() {
	int N, M;
	cin >> N >> M;
	
	multiset<ull> A;
	ull a;
	
	for(uint i=0; i<N; i++) {
		cin >> a;
		A.insert(a);
	}
	
	for(uint i=0; i<M; i++) {
		ull mx = max_element(A.begin(), A.end());
		uint md = distance(vec.begin(), mx);
		ull a = mx / 2;
		cout << a << " " << *A.begin() << endl;
		A.erase(A.begin() + md);
		A.insert(a);
	}
	
	cout << accumulate(A.begin(), A.end(), 0);
	
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:26: error: 'max_element' was not declared in this scope
   21 |                 ull mx = max_element(A.begin(), A.end());
      |                          ^~~~~~~~~~~
a.cc:22:36: error: 'vec' was not declared in this scope
   22 |                 uint md = distance(vec.begin(), mx);
      |                                    ^~~
a.cc:25:35: error: no match for 'operator+' (operand types are 'std::multiset<long long unsigned int>::iterator' {aka 'std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned int> >::const_iterator'} and 'uint' {aka 'unsigned int'})
   25 |                 A.erase(A.begin() + md);
      |                         ~~~~~~~~~ ^ ~~
      |                                |    |
      |                                |    uint {aka unsigned int}
      |                                std::multiset<long long unsigned int>::iterator {aka std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned 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:25:37: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'uint' {aka 'unsigned int'}
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'uint' {aka 'unsigned int'}
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
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:25:37: note:   'std::multiset<long long unsigned int>::iterator' {aka 'std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   mismatched types 'const _CharT*' and 'std::_Rb_tree_const_iterator<long long unsigned int>'
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'uint' {aka 'unsigned int'}
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   'std::multiset<long long unsigned int>::iterator' {aka 'std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   'std::multiset<long long unsigned int>::iterator' {aka 'std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   'std::multiset<long long unsigned int>::iterator' {aka 'std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned int> >::const_iterator'} is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   'std::multiset<long long unsigned int>::iterator' {aka 'std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned int> >::const_iterator'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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:25:37: note:   'std::multiset<long long unsigned int>::iterator' {aka 'std::_Rb_tree<long long unsigned int, long long unsigned int, std::_Identity<long long unsigned int>, std::less<long long unsigned int>, std::allocator<long long unsigned int> >::const_iterator'} is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   25 |                 A.erase(A.begin() + md);
      |                                     ^~
/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