Language: C++

#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <map>
#include <queue>
#include <ctime>
#include <cmath>

using namespace std;

#define forn(I,N) for (int I = 0; I < (N); ++I)
#define fornd(I,N) for (int I = (N) - 1; I >= 0; --I)
#define forab(I,A,B) for (int I = (A); I <= (B); ++I)
#define forabd(I,A,B) for (int I= (B); I >= (A); --I)
#define FOREACH(I,A) for (__typeof__(A)::iterator I=A.begin(); I<A.end(); I++)
#define all(V) (V).begin(), (V).end()
#define pb push_back
#define mp make_pair

typedef long long int ll;

ll gcd(ll a, ll b) { return b == 0 ? a : gcd(b, a % b); }

const ll mod = 1000000007;

int main() {
  int N, K;
  cin >> N >> K;

  vector<ll> V(N);
  forn(i, N) {
    cin >> V[i];
  }

  ll ans = 0;
  forn(i, N) {
    forn(j, N - i) {
      if (i + j <= K) {
        vector<ll> neg;
        int buf = 0;
        forn(k, i) {
          buf += V[k];
          if (V[k] < 0) {
            neg.pb(V[k]);
          }
        }
        forn(k, j) {
          buf += V[N - k - 1];
          if (V[N - k - 1] < 0) {
            neg.pb(V[N - k - 1]);
          }
        }

        ans = max(ans, buf);

        sort(neg.begin(), neg.end());
        // cout << min(K - i - j, (int)neg.size()) << endl;
        forn(k, min(K - i - j, (int)neg.size())) {
          buf -= neg[k];
          ans = max(ans, buf);
        }
      }
    }
  }

  cout << ans << endl;

  return 0;
}



Compiler output:
a.cc: In function 'int main()':
a.cc:58:18: error: no matching function for call to 'max(ll&, int&)'
   58 |         ans = max(ans, buf);
      |               ~~~^~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 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_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:58:18: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   58 |         ans = max(ans, buf);
      |               ~~~^~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:6:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:58:18: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   58 |         ans = max(ans, buf);
      |               ~~~^~~~~~~~~~
a.cc:64:20: error: no matching function for call to 'max(ll&, int&)'
   64 |           ans = max(ans, buf);
      |                 ~~~^~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:64:20: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   64 |           ans = max(ans, buf);
      |                 ~~~^~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:64:20: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   64 |           ans = max(ans, buf);
      |                 ~~~^~~~~~~~~~