Language: C++

#include<bits/stdc++.h>
#define ll long long
#define nl "\n"
using namespace std;

void solve()
{
	ll n, m, k,x;
	cin>>n>>m>>k;
	vector<ll> a(n+1),b(m+1);
	a[0] = 0, b[0] = 0;
	for(ll i = 1; i<=n; i++)
	{
		cin>>x;
		a[i] = a[i-1] + x;
	}
	for(ll i = 1; i<=m; i++)
	{
		cin>>x;
		b[i] = b[i-1] + x;
	}
	ll ans = 0;
	for(ll i = 0; i<=n && a[i] <= k; i++)
	{
		ll tm = k - a[i];
		auto low = lower_bound(b.begin(), b.end(), tm);
		ll idx = low - b.begin();
//		cout<<tm<<" "<< idx<<nl;
		if(idx!= b.end()&&b[idx] <= tm) 
			ans = max(ans, i+idx);
		else
			ans = max(ans, i+idx-1);
	}
	cout<<ans<<nl;
}
int main()
{
	solve();
	return 0;
}

Compiler output:
a.cc: In function 'void solve()':
a.cc:29:23: error: no match for 'operator!=' (operand types are 'long long int' and 'std::vector<long long int>::iterator')
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                    ~~~^~ ~~~~~~~
      |                    |          |
      |                    |          std::vector<long long int>::iterator
      |                    long long 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:1132:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1132 |     operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1132:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/regex.h:1212:5: 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>&)'
 1212 |     operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1212:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/regex.h:1305:5: 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>&)'
 1305 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1305:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/regex.h:1379:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1379 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1379:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   'std::vector<long long int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/regex.h:1473:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1473 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1473:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/regex.h:1547:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1547 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1547:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   'std::vector<long long int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/regex.h:1647:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1647 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1647:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/regex.h:2213:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator!=(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2213 |     operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2213:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::__cxx11::match_results<_BiIter, _Alloc>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
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:1052:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator!=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1052 |     operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1052:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::pair<_T1, _T2>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:455:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  455 |     operator!=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:455:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/stl_iterator.h:500:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  500 |     operator!=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:500:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1686 |     operator!=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1753 |     operator!=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
In file included from /usr/include/c++/14/bits/char_traits.h:42,
                 from /usr/include/c++/14/string:42,
                 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/postypes.h:197:5: note: candidate: 'template<class _StateT> bool std::operator!=(const fpos<_StateT>&, const fpos<_StateT>&)'
  197 |     operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:197:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::fpos<_StateT>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
In file included from /usr/include/c++/14/string:43:
/usr/include/c++/14/bits/allocator.h:243:5: note: candidate: 'template<class _T1, class _T2> bool std::operator!=(const allocator<_CharT>&, const allocator<_T2>&)'
  243 |     operator!=(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:243:5: note:   template argument deduction/substitution failed:
a.cc:29:32: note:   mismatched types 'const std::allocator<_CharT>' and 'long long int'
   29 |                 if(idx!= b.end()&&b[idx] <= tm)
      |                                ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:651:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator!=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  651 |