Language: C++

#include <bits/stdc++.h>
#include <unordered_map>
#include <unordered_set>

using namespace std;

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

typedef long long ll;
//No change above here

const ll maxi = 302;
ll mod = (1e9 + 7);

//function for power
ll power(ll x, ll n) {
	ll res = 1;
	x %= mod;
	while (n) {
		if (n & 1)
			res = (res * x) % mod;
		x = (x * x) % mod;
		n >>= 1;
	}
	return res;
}

ll sum_digits(ll n)
{
	ll ret = 0;
	while (n)
	{
		ret += n % 10;
		n /= 10;
	}
	return ret;
}

ll dir[4][2] = { {1, 0}, {-1, 0}, {0, 1}, {0, -1} };

ll p, q;
bool valid(ll i, ll j) { return i >= 1 && i <= p && j >= 1 && j <= q; }

//declare needed things here



int main()
{
	IOS;
	ll n, m, k;
	cin >> n >> m >> k;
	vector<ll> a(n + 1, 0);
	vector<ll> b(m + 1, 0);
	for (int i = 1; i <= n; ++i)
	{
		cin >> a[i];
		a[i] += a[i - 1];
	}
	for (int i = 1; i <= m; ++i)
	{
		cin >> b[i];
		b[i] += b[i - 1];
	}
	ll ans = 0;
	for (int i = 0; i <= n; ++i)
	{
		ll find = k - a[i];
		if (find < 0)
			break;
		auto it = upper_bound(b.begin(), b.end(), find);
		ans = max(ans, it - b.begin() + i-1);
	}
	cout << ans << endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:72:26: error: no matching function for call to 'max(ll&, __gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type)'
   72 |                 ans = max(ans, it - b.begin() + 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:72:26: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and '__gnu_cxx::__normal_iterator<long long int*, std::vector<long long int> >::difference_type' {aka 'long int'})
   72 |                 ans = max(ans, it - b.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:
/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:72:26: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   72 |                 ans = max(ans, it - b.begin() + i-1);
      |                       ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~