Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  int n,k;
  cin>>n>>k;
  vector<int> a(n);
  for(int i=0;i<n;i++){
    cin>>a.at(i);
  }
  sort(a);
  reverse(a);
  int c=0;
  for(int i=0;i<k;i++){
    c+=a.at(i);
  }
  cout<<c;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:7: error: no matching function for call to 'sort(std::vector<int>&)'
   10 |   sort(a);
      |   ~~~~^~~
In file included from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algo.h:4762:5: note: candidate: 'template<class _RAIter> void std::sort(_RAIter, _RAIter)'
 4762 |     sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
      |     ^~~~
/usr/include/c++/14/bits/stl_algo.h:4762:5: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_algo.h:4793:5: note: candidate: 'template<class _RAIter, class _Compare> void std::sort(_RAIter, _RAIter, _Compare)'
 4793 |     sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
      |     ^~~~
/usr/include/c++/14/bits/stl_algo.h:4793:5: note:   candidate expects 3 arguments, 1 provided
In file included from /usr/include/c++/14/algorithm:86:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:292:1: note: candidate: 'template<class _ExecutionPolicy, class _RandomAccessIterator, class _Compare> __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void> std::sort(_ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Compare)'
  292 | sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp);
      | ^~~~
/usr/include/c++/14/pstl/glue_algorithm_defs.h:292:1: note:   candidate expects 4 arguments, 1 provided
/usr/include/c++/14/pstl/glue_algorithm_defs.h:296:1: note: candidate: 'template<class _ExecutionPolicy, class _RandomAccessIterator> __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void> std::sort(_ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator)'
  296 | sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
      | ^~~~
/usr/include/c++/14/pstl/glue_algorithm_defs.h:296:1: note:   candidate expects 3 arguments, 1 provided
a.cc:11:10: error: no matching function for call to 'reverse(std::vector<int>&)'
   11 |   reverse(a);
      |   ~~~~~~~^~~
/usr/include/c++/14/bits/stl_algo.h:1083:5: note: candidate: 'template<class _BIter> void std::reverse(_BIter, _BIter)'
 1083 |     reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
      |     ^~~~~~~
/usr/include/c++/14/bits/stl_algo.h:1083:5: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/pstl/glue_algorithm_defs.h:249:1: note: candidate: 'template<class _ExecutionPolicy, class _BidirectionalIterator> __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void> std::reverse(_ExecutionPolicy&&, _BidirectionalIterator, _BidirectionalIterator)'
  249 | reverse(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last);
      | ^~~~~~~
/usr/include/c++/14/pstl/glue_algorithm_defs.h:249:1: note:   candidate expects 3 arguments, 1 provided