Language: C++

#include <bits/stdc++.h>
#define MOD (long long)(1E9+7)
#define rep(i, n) for(int i = 0; i < n; i++)

using namespace std;


long long extgcd(long long a)
{
	long long b = MOD;
	long long u = 1, v = 0, q; 
	while ( b > 0 ) {
		q = a / b; 
		a -= q * b; swap(a,b);
		u -= q * v; swap(u,v);
	}
	u %= MOD;
	while (u<0)
		u+=MOD;
	return u;
}
long long comb(long long n,long long k)
{
	long long t = 1;
	long long j = k;
	for(long long i = n; i  >= n-k+1; i--) {
		t *= i;
		t %= MOD;
		t *= extgcd(j);
		t %= MOD;
		j--;
	}  
  	while (t<0)
		t += MOD;
	return t;
}

int main(){
	long long n,k;
	cin >> n;
	vector<long> a(n);
  	pair<long, int> ss(n);
  	
  	rep(i, n) {
    	cin >> a[i];
      	ss[i] = {a[i], i};
    }
  	sort(ss.begin(), ss.end());
  	reverse(ss.begin(), ss.end());
  	int fr=0, bk=0;
	k=0;
  	int t = 0;
  	rep(i, n) {
      	t = ss[i].second();
  		if(abs(t - fr) >= abs((n-bk)-t) ) {
        	fr++;
          	k += ss[i].first()*abs(t-fr);
        } else {
          	k += ss[i].first()*abs((n-bk)-t);
          	bk++;
        }
    }
    
	cout << k << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:42:29: error: no matching function for call to 'std::pair<long int, int>::pair(long long int&)'
   42 |         pair<long, int> ss(n);
      |                             ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_pair.h:913:28: note: candidate: 'template<class _U1, class _U2, typename std::enable_if<(std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_MoveConstructiblePair<_U1, _U2>() && (! std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_ImplicitlyMoveConvertiblePair<_U1, _U2>())), bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(std::pair<_U1, _U2>&&) [with _U2 = _U1; typename std::enable_if<(std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_MoveConstructiblePair<_U1, _U2>() && (! std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_ImplicitlyMoveConvertiblePair<_U1, _U2>())), bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  913 |         explicit constexpr pair(pair<_U1, _U2>&& __p)
      |                            ^~~~
/usr/include/c++/14/bits/stl_pair.h:913:28: note:   template argument deduction/substitution failed:
a.cc:42:29: note:   mismatched types 'std::pair<_T1, _T2>' and 'long long int'
   42 |         pair<long, int> ss(n);
      |                             ^
/usr/include/c++/14/bits/stl_pair.h:902:19: note: candidate: 'template<class _U1, class _U2, typename std::enable_if<(std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_MoveConstructiblePair<_U1, _U2>() && std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_ImplicitlyMoveConvertiblePair<_U1, _U2>()), bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(std::pair<_U1, _U2>&&) [with _U2 = _U1; typename std::enable_if<(std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_MoveConstructiblePair<_U1, _U2>() && std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_ImplicitlyMoveConvertiblePair<_U1, _U2>()), bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  902 |         constexpr pair(pair<_U1, _U2>&& __p)
      |                   ^~~~
/usr/include/c++/14/bits/stl_pair.h:902:19: note:   template argument deduction/substitution failed:
a.cc:42:29: note:   mismatched types 'std::pair<_T1, _T2>' and 'long long int'
   42 |         pair<long, int> ss(n);
      |                             ^
/usr/include/c++/14/bits/stl_pair.h:891:28: note: candidate: 'template<class _U1, class _U2, typename std::enable_if<(_MoveConstructiblePair<_U1, _U2>() && (! _ImplicitlyMoveConvertiblePair<_U1, _U2>())), bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(_U1&&, _U2&&) [with _U2 = _U1; typename std::enable_if<(std::_PCC<true, _T1, _T2>::_MoveConstructiblePair<_U1, _U2>() && (! std::_PCC<true, _T1, _T2>::_ImplicitlyMoveConvertiblePair<_U1, _U2>())), bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  891 |         explicit constexpr pair(_U1&& __x, _U2&& __y)
      |                            ^~~~
/usr/include/c++/14/bits/stl_pair.h:891:28: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_pair.h:881:19: note: candidate: 'template<class _U1, class _U2, typename std::enable_if<(_MoveConstructiblePair<_U1, _U2>() && _ImplicitlyMoveConvertiblePair<_U1, _U2>()), bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(_U1&&, _U2&&) [with _U2 = _U1; typename std::enable_if<(std::_PCC<true, _T1, _T2>::_MoveConstructiblePair<_U1, _U2>() && std::_PCC<true, _T1, _T2>::_ImplicitlyMoveConvertiblePair<_U1, _U2>()), bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  881 |         constexpr pair(_U1&& __x, _U2&& __y)
      |                   ^~~~
/usr/include/c++/14/bits/stl_pair.h:881:19: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_pair.h:869:9: note: candidate: 'template<class _U2, typename std::enable_if<std::__and_<std::is_pointer<long int>, std::__not_<std::is_reference<_Tp> >, std::is_constructible<int, _U2>, std::__not_<std::is_constructible<int, const _U1&> >, std::__not_<std::is_convertible<_U2, int> > >::value, bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(__zero_as_null_pointer_constant, _U2&&, ...) [with typename std::enable_if<std::__and_<std::is_pointer<_Tp>, std::__not_<std::is_reference<_U1> >, std::is_constructible<_T2, _U2>, std::__not_<std::is_constructible<_T1, const _U1&> >, std::__not_<std::is_convertible<_U2, _T2> > >::value, bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  869 |         pair(__zero_as_null_pointer_constant, _U2&& __y, ...)
      |         ^~~~
/usr/include/c++/14/bits/stl_pair.h:869:9: note:   candidate expects at least 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_pair.h:856:9: note: candidate: 'template<class _U2, typename std::enable_if<std::__and_<std::is_pointer<long int>, std::__not_<std::is_reference<_Tp> >, std::is_constructible<int, _U2>, std::__not_<std::is_constructible<int, const _U1&> >, std::is_convertible<_U2, int> >::value, bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(__zero_as_null_pointer_constant, _U2&&, ...) [with typename std::enable_if<std::__and_<std::is_pointer<_Tp>, std::__not_<std::is_reference<_U1> >, std::is_constructible<_T2, _U2>, std::__not_<std::is_constructible<_T1, const _U1&> >, std::is_convertible<_U2, _T2> >::value, bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  856 |         pair(__zero_as_null_pointer_constant, _U2&& __y, ...)
      |         ^~~~
/usr/include/c++/14/bits/stl_pair.h:856:9: note:   candidate expects at least 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_pair.h:843:9: note: candidate: 'template<class _U1, typename std::enable_if<std::__and_<std::__not_<std::is_reference<_Tp> >, std::is_pointer<int>, std::is_constructible<long int, _U2>, std::__not_<std::is_constructible<long int, const _U1&> >, std::__not_<std::is_convertible<_U2, long int> > >::value, bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(_U1&&, __zero_as_null_pointer_constant, ...) [with typename std::enable_if<std::__and_<std::__not_<std::is_reference<_U1> >, std::is_pointer<_T2>, std::is_constructible<_T1, _U1>, std::__not_<std::is_constructible<_T1, const _U1&> >, std::__not_<std::is_convertible<_U1, _T1> > >::value, bool>::type <anonymous> = _U1; _T1 = long int; _T2 = int]'
  843 |         pair(_U1&& __x, __zero_as_null_pointer_constant, ...)
      |         ^~~~
/usr/include/c++/14/bits/stl_pair.h:843:9: note:   candidate expects at least 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_pair.h:830:9: note: candidate: 'template<class _U1, typename std::enable_if<std::__and_<std::__not_<std::is_reference<_Tp> >, std::is_pointer<int>, std::is_constructible<long int, _U2>, std::__not_<std::is_constructible<long int, const _U1&> >, std::is_convertible<_U2, long int> >::value, bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(_U1&&, __zero_as_null_pointer_constant, ...) [with typename std::enable_if<std::__and_<std::__not_<std::is_reference<_U1> >, std::is_pointer<_T2>, std::is_constructible<_T1, _U1>, std::__not_<std::is_constructible<_T1, const _U1&> >, std::is_convertible<_U1, _T1> >::value, bool>::type <anonymous> = _U1; _T1 = long int; _T2 = int]'
  830 |         pair(_U1&& __x, __zero_as_null_pointer_constant, ...)
      |         ^~~~
/usr/include/c++/14/bits/stl_pair.h:830:9: note:   candidate expects at least 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_pair.h:789:28: note: candidate: 'template<class _U1, class _U2, typename std::enable_if<(std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_ConstructiblePair<_U1, _U2>() && (! std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_ImplicitlyConvertiblePair<_U1, _U2>())), bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(const std::pair<_U1, _U2>&) [with _U2 = _U1; typename std::enable_if<(std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_ConstructiblePair<_U1, _U2>() && (! std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_ImplicitlyConvertiblePair<_U1, _U2>())), bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  789 |         explicit constexpr pair(const pair<_U1, _U2>& __p)
      |                            ^~~~
/usr/include/c++/14/bits/stl_pair.h:789:28: note:   template argument deduction/substitution failed:
a.cc:42:29: note:   mismatched types 'const std::pair<_T1, _T2>' and 'long long int'
   42 |         pair<long, int> ss(n);
      |                             ^
/usr/include/c++/14/bits/stl_pair.h:779:19: note: candidate: 'template<class _U1, class _U2, typename std::enable_if<(std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_ConstructiblePair<_U1, _U2>() && std::_PCC<((! std::is_same<long int, _U1>::value) || (! std::is_same<int, _U2>::value)), long int, int>::_ImplicitlyConvertiblePair<_U1, _U2>()), bool>::type <anonymous> > constexpr std::pair<_T1, _T2>::pair(const std::pair<_U1, _U2>&) [with _U2 = _U1; typename std::enable_if<(std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_ConstructiblePair<_U1, _U2>() && std::_PCC<((! std::is_same<_T1, _U1>::value) || (! std::is_same<_T2, _U2>::value)), _T1, _T2>::_ImplicitlyConvertiblePair<_U1, _U2>()), bool>::type <anonymous> = _U2; _T1 = long int; _T2 = int]'
  779 |         constexpr pair(const pair<_U1, _U2>& __p)
      |                   ^~~~
/usr/include/c++/14/bits/stl_pair.h:779:19: note:   template argument deduction/substitution