Language: C++

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <iomanip>
#include <vector>
#include <string.h>
#include <math.h>
#include <algorithm>

using namespace std;



int main() {
	int n, m, k;
	cin >> n >> m >> k;

	vector<int> a(n+1);
	vector<int> b(m+1);

	for (int i = 1;i <= n;i++) {
		cin >> a[i];
	}

	for (int i = 1;i <= m;i++) {
		cin >> b[i];
	}

	long long sum = 0;
	vector<long long> c(m+1);

	for (int i = 1; i <= m;i++) {
		sum += b[i];
		c[i] = sum;
	}

	int ans = 0;
	long long tmp = k;

	for (int i = 0;i <= n;i++) {
		
		tmp -= a[i];
		if (tmp < 0) {
			break;
		}

		auto Iter = upper_bound(c.begin(), c.end(), tmp);
		if (Iter <= c.end()) {
			ans = max(ans, (Iter - c.begin()) + i - 1);
		}
		
		
	}

	cout << ans << endl;

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:49:34: error: no matching function for call to 'max(int&, __gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type)'
   49 |                         ans = max(ans, (Iter - c.begin()) + i - 1);
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:3:
/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:49:34: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type' {aka 'long int'})
   49 |                         ans = max(ans, (Iter - c.begin()) + 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,
                 from a.cc:8:
/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:49:34: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   49 |                         ans = max(ans, (Iter - c.begin()) + i - 1);
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~