Language: C++

#include <iostream>
#include <algorithm>
#include <vector>


int main()
{
    long long  n,m,k; std::cin >> n >> m >> k;
    // long long  a[n+1], b[m+1];
    std::vector<long long>  a{n+1}, b{m+1};
    a[0]=0; b[0]=0;
    for (int i=1;i<n+1;i++)
        std::cin >> a[i];
    for (int i=1; i<m+1; i++)
        std::cin >> b[i];
    
    for (int i=1; i<n+1; i++)
        a[i]+=a[i-1];
    for (int i=1; i<m+1; i++)
        b[i]+=b[i-1];

    i long long ns=0, r=m;
    for (int i=0; i<n+1; i++)
    {
        if(a[i]>k) break;
        while (a[i]+b[r]>k)
            r--;
        ans = std::max({ans, i+r});
    }
    
    std::cout << ans;

    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:22:5: error: 'i' was not declared in this scope
   22 |     i long long ns=0, r=m;
      |     ^
a.cc:26:23: error: 'r' was not declared in this scope
   26 |         while (a[i]+b[r]>k)
      |                       ^
a.cc:28:9: error: 'ans' was not declared in this scope; did you mean 'abs'?
   28 |         ans = std::max({ans, i+r});
      |         ^~~
      |         abs
a.cc:28:32: error: 'r' was not declared in this scope
   28 |         ans = std::max({ans, i+r});
      |                                ^
a.cc:28:23: error: no matching function for call to 'max(<brace-enclosed initializer list>)'
   28 |         ans = std::max({ans, i+r});
      |               ~~~~~~~~^~~~~~~~~~~~
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:   candidate expects 2 arguments, 1 provided
/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, 1 provided
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:2:
/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:   template argument deduction/substitution failed:
/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:   candidate expects 2 arguments, 1 provided
a.cc:31:18: error: 'ans' was not declared in this scope; did you mean 'abs'?
   31 |     std::cout << ans;
      |                  ^~~
      |                  abs