Language: C++

// Copyright 2020 yaito3014
#include <bits/stdc++.h>

int main() {
  using namespace std;
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int N, M, K;
  cin >> N >> M >> K;
  vector<long long> A(N + 1, 0), B(M + 1, 0);
  auto iter = istream_iterator<int>(cin);
  copy_n(iter, N, next(begin(A)));
  copy_n(iter, M, next(begin(B)));
  partial_sum(cbegin(A), cend(A), begin(A));
  partial_sum(cbegin(B), cend(B), begin(B));
  int ans = 0;
  for (int i = 0; i <= N; ++i)
    if (auto iter = lower_bound(cbegin(B), cend(B), max(0ll, K - A[i]) + 1);
        iter == cend(B) || A[i] + *prev(iter) <= K)
      ans = max<int>(ans, i + max(0, distance(cbegin(B), iter) - 1));
  cout << ans << '\n';
}


Compiler output:
a.cc: In function 'int main()':
a.cc:20:34: error: no matching function for call to 'max(int, std::__iterator_traits<__gnu_cxx::__normal_iterator<const long long int*, std::vector<long long int> >, void>::difference_type)'
   20 |       ans = max<int>(ans, i + max(0, distance(cbegin(B), iter) - 1));
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:2:
/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:20:34: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'std::__iterator_traits<__gnu_cxx::__normal_iterator<const long long int*, std::vector<long long int> >, void>::difference_type' {aka 'long int'})
   20 |       ans = max<int>(ans, i + max(0, distance(cbegin(B), iter) - 1));
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/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:
/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:20:34: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   20 |       ans = max<int>(ans, i + max(0, distance(cbegin(B), iter) - 1));
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~