Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  int n;
  cin>>n;
  vector<int>b(n);
  int a[n];
  for (int i=0;i<n;i++)cin>>b.at(i);
  
  sort(b.begin(),b.end());
  reverse(b.begin(),b.end());
  for(int i=0;i<n;i++)a[i]=b.at(i);
  
  vector<int>c(n*(n+1)/2);
  int k=0;
  for(i=0;i<n;i++){
    for(j=0;j<n;j++){
      if(i>j)continue;
      else{
        c.at(k)=a[(j-i+1)/2+i];
        k++;
      }
    }
  }
  sort(c.begin(),c.end());
  reverse(c.begin(),end());
  cout<<c.at((n*(n+1)/2)/2)<<endl;
}
  
  

Compiler output:
a.cc: In function 'int main()':
a.cc:17:7: error: 'i' was not declared in this scope
   17 |   for(i=0;i<n;i++){
      |       ^
a.cc:18:9: error: 'j' was not declared in this scope
   18 |     for(j=0;j<n;j++){
      |         ^
a.cc:27:24: error: no matching function for call to 'end()'
   27 |   reverse(c.begin(),end());
      |                     ~~~^~
In file included from /usr/include/c++/14/bits/algorithmfwd.h:39,
                 from /usr/include/c++/14/bits/stl_algo.h:59,
                 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/initializer_list:99:5: note: candidate: 'template<class _Tp> constexpr const _Tp* std::end(initializer_list<_Tp>)'
   99 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
/usr/include/c++/14/initializer_list:99:5: note:   candidate expects 1 argument, 0 provided
In file included from /usr/include/c++/14/string:53,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/range_access.h:74:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:85:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:106:5: note: candidate: 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:   candidate expects 1 argument, 0 provided
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/valarray:1249:5: note: candidate: 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
 1249 |     end(valarray<_Tp>& __va) noexcept
      |     ^~~
/usr/include/c++/14/valarray:1249:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/valarray:1265:5: note: candidate: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
 1265 |     end(const valarray<_Tp>& __va) noexcept
      |     ^~~
/usr/include/c++/14/valarray:1265:5: note:   candidate expects 1 argument, 0 provided