Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef vector<int> vi;

int main(){
  int N, K;cin>>N>>K;
  vi a;
  for (int i=0;i<N;++i){
    int a_;cin>>a_;a.push_back(a_);
  }

  int left[N][K], right[N][K];
  memset(left, -1, sizeof(left));
  memset(right, -1, sizeof(right));

  left[0][0]=1;left[0][a[0]]=1;
  right[N-1][0]=1;right[N-1][a[N-1]]=1;

  for (int i=0;i<N;++i){
    for (int j=0;j<K;++j){
      if(left[i][j]==1||(j>=a[i+1]&&left[i][j-a[i+1]]==1)) left[i+1][k]=1;
    }
  }

  for (int i=N-1;i>=1;--i){
    for (int j=0;j<K;++j){
      if(left[i][j]==1||(j>=a[i-1]&&left[i][j-a[i-1]]==1)) left[i-1][k]=1;
    }
  }

  vi l_sum[N], r_sum[N];
  int ans=0;

  for (int i=0;i<N;++i){
    for (int j=0;j<K;++j){
      if(left[i][j]==1)l_sum[i].push_back(j);
      if(right[i][j]==1)r_sum[i].push_back(j);
    }
  }

  int x=lower_bound(l_sum[N-2].begin(), l_sum[N-2].end(), K-a[N-1])-l_sum[N-2].begin();
  if(l_sum[x]>=K) ans++;

  x=lower_bound(r_sum[1].begin(), r_sum[1].end(), K-a[0])-r_sum[1].begin();
  if(r_sum[x]>=K) ans++;

  for (int i=1;i<N-1;++i){
    int L=l_sum[i-1].size();
    for (int l=0;l<L;++l){
      x=lower_bound(r_sum[i+1].begin(), r_sum[i+1].end(), K-l_sum[i-1][l]-a[i])-l_sum[i-1].begin();
      if(r_sum[x]+l_sum[i-1][l]>=K) ans++;
    }
  }

  cout << ans << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:70: error: 'k' was not declared in this scope
   21 |       if(left[i][j]==1||(j>=a[i+1]&&left[i][j-a[i+1]]==1)) left[i+1][k]=1;
      |                                                                      ^
a.cc:27:70: error: 'k' was not declared in this scope
   27 |       if(left[i][j]==1||(j>=a[i-1]&&left[i][j-a[i-1]]==1)) left[i-1][k]=1;
      |                                                                      ^
a.cc:42:14: error: no match for 'operator>=' (operand types are 'vi' {aka 'std::vector<int>'} and 'int')
   42 |   if(l_sum[x]>=K) ans++;
      |      ~~~~~~~~^~~
      |             |  |
      |             |  int
      |             vi {aka std::vector<int>}
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1165:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator>=(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1165 |     operator>=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1165:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/regex.h:1248:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator>=(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1248 |     operator>=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1248:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/regex.h:1341:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator>=(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1341 |     operator>=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1341:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/regex.h:1415:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator>=(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1415 |     operator>=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1415:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/regex.h:1509:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator>=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1509 |     operator>=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1509:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/regex.h:1586:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator>=(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1586 |     operator>=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1586:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/regex.h:1686:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator>=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1686 |     operator>=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1686:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
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:
/usr/include/c++/14/bits/stl_pair.h:1070:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator>=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1070 |     operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1070:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::pair<_T1, _T2>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:476:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  476 |     operator>=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:476:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/stl_iterator.h:520:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  520 |     operator>=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:520:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1724 |     operator>=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::move_iterator<_IteratorL>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1781 |     operator>=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'vi' {aka 'std::vector<int>'} is not derived from 'const std::move_iterator<_IteratorL>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/string_view:739:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  739 |     operator>=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:739:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'std::vector<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/string_view:746:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  746 |     operator>=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:746:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   'std::vector<int>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/string_view:754:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  754 |     operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:754:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   42 |   if(l_sum[x]>=K) ans++;
      |                ^
/usr/include/c++/14/bits/basic_string.h:3997:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator>=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3997 |     operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3997:5: note:   template argument deduction/substitution failed:
a.cc:42:16: note:   '