Language: C++

#include <bits/stdc++.h>
#define readvec(n, X, SX) for(int i = 1; i <= n; i++) \
    { \
        cin >> X[i]; \
        SX[i] = SX[i-1] + X[i]; \
    }
using namespace std;
int N,M, A[200005], B[200005], result;
int SA[200005], SB[200005], K;
int main() {
    cin >> N >> M >> K;
    readvec(N, A, SA);
    readvec(M, B, SB);
    int MN = max(M, N);
    for(int i = N + 1;i <= MN + 1; i++)
        SA[i] = 1e16+1;
    for(int i = M + 1; i <= MN + 1; i++)
        SB[i] = 1e16+1;
    for(int i = 0; i <= N; i++)
        if(K >= SA[i])
            result = max(result, (SB - upper_bound(SB, SB + MN + 1, K - SA[i])) + i - 1);
    cout << result;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:16:21: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+16' to '2147483647' [-Woverflow]
   16 |         SA[i] = 1e16+1;
      |                 ~~~~^~
a.cc:18:21: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+16' to '2147483647' [-Woverflow]
   18 |         SB[i] = 1e16+1;
      |                 ~~~~^~
a.cc:21:25: error: no matching function for call to 'max(int&, long int)'
   21 |             result = max(result, (SB - upper_bound(SB, SB + MN + 1, K - SA[i])) + i - 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: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:21:25: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long int')
   21 |             result = max(result, (SB - upper_bound(SB, SB + MN + 1, K - SA[i])) + i - 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:21:25: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   21 |             result = max(result, (SB - upper_bound(SB, SB + MN + 1, K - SA[i])) + i - 1);
      |                      ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~