Language: C++

#include <bits/stdc++.h>
#define WHOLE(v) (v).begin(), (v).end()
#define REV_WHOLE(v) (v).rbegin(), (v).rend()
using i64 = int64_t;
using namespace std;
template <size_t I, class H, class... T> struct TupleReaderWriter{static tuple<H,T...> r(istream&i){H v;i>>v;return tuple_cat(tuple<H>(v),TupleReaderWriter<sizeof...(T)-1,T...>::r(i));}static void w(ostream&o,tuple<H,T...>&t,string d){TupleReaderWriter<I-1,H,T...>::w(o,t,d);o<<d<<get<I>(t);}};
template <class H, class... T> struct TupleReaderWriter<0,H,T...>{static tuple<H,T...> r(istream&i){H v;i>>v;return tuple<H>(v);}static void w(ostream&o,tuple<H,T...>&t,string d){o<<get<0>(t);}};
template <class... T> istream& operator>>(istream&i,tuple<T...>& t) { t = TupleReaderWriter<sizeof...(T), T...>::r(i); return i; }
template <class... T> ostream& operator<<(ostream& o, tuple<T...>& t) { string delim = " "; TupleReaderWriter<sizeof...(T) - 1, T...>::w(o, t, delim); return o; }
template<typename T> using rev_priority_queue = priority_queue<T, vector<T>, greater<T>>;
template<typename T> using vector2d = vector<vector<T>>;
void R_YESNO(bool p) { cout << (p ? "YES" : "NO") << endl; }
void R_YesNo(bool p) { cout << (p ? "Yes" : "No") << endl; }

// 二分探索（改）
// judge を満たすような下限を求める
// left:[X] 定義域の下限
// right:[X] 定義域の上限
// judge:[X -> bool] X を評価する関数
// lower:[bool] falseにすると代わりに上限を求める
// eps:[X] 終了距離

template <typename X>
X BinSearch(X left, X right, function<bool(X)> judge, bool lower = true, X eps = 1) {
    while (right - left > eps) {
        X mid = (right + left) / 2;
        if (judge(mid) == lower) {
            right = mid;
        } else {
            left = mid;
        }
    }
    return lower ? right : left;
}

int64_t divceil(int64_t a, int64_t b) {
    return a / b + (a > 0 && a % b ? 1 : 0);
}

int main() {
    i64 N, K;
    cin >> N >> K;
    vector<i64> A(N), F(N);
    for(auto &x : A) cin >> x;
    for(auto &x : F) cin >> x;
    sort(WHOLE(A));
    sort(REV_WHOLE(F));

    i64 ans = BinSearch<i64>(-1, 1e16, [&](i64 T) -> bool {
        i64 k = 0;
        for(int i = 0; i < N; i++) {
            k += max(0, A[i] - T / F[i]);
        }
        return k <= K;
    }, true);

    cout << ans << endl;

    return 0;
}

Compiler output:
a.cc: In lambda function:
a.cc:52:21: error: no matching function for call to 'max(int, __gnu_cxx::__alloc_traits<std::allocator<long int>, long int>::value_type)'
   52 |             k += max(0, A[i] - T / F[i]);
      |                  ~~~^~~~~~~~~~~~~~~~~~~~
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:52:21: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__alloc_traits<std::allocator<long int>, long int>::value_type' {aka 'long int'})
   52 |             k += max(0, A[i] - T / F[i]);
      |                  ~~~^~~~~~~~~~~~~~~~~~~~
/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:52:21: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   52 |             k += max(0, A[i] - T / F[i]);
      |                  ~~~^~~~~~~~~~~~~~~~~~~~