Language: C++

/*{{{*/
//#define HOME
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
using namespace std;

#define MP make_pair
#define MT make_tuple
#define PB push_back
#define EB emplace_back
#define F first
#define S second

template<class T> void _R(T &_x) { cin >> _x; }
void _R(int &_x) { scanf("%d", &_x); }
void _R(int64_t &_x) { scanf("%" SCNd64, &_x); }
void _R(double &_x) { scanf("%lf", &_x); }
void _R(char &_x) { scanf(" %c", &_x); }
void _R(char *_x) { scanf("%s", _x); }
template<class T, class U> void _R(pair<T, U> &_x) {_R(_x.F); _R(_x.S);}
void R() {}
template<class T, class... U> void R(T &_head, U &... _tail) { _R(_head); R(_tail...); }

template<class T> void _W(const T &_x) { cout << _x; }
void _W(const int &_x) { printf("%d", _x); }
void _W(const int64_t &_x) { printf("%" PRId64, _x); }
void _W(const double &_x) { printf("%.16f", _x); }
void _W(const char &_x) { putchar(_x); }
void _W(const char *_x) { printf("%s", _x); }
template<class T, class U> void _W(const pair<T, U> &_x) {_W(_x.F); putchar(' '); _W(_x.S);}
template<class T> void _W(const vector<T> &_x) { for (auto i = _x.begin(); i != _x.end(); _W(*i++)) if (i != _x.cbegin()) putchar(' '); }
void W() {}
template<class T, class... U> void W(const T &_head, const U &... _tail) { _W(_head); putchar(sizeof...(_tail) ? ' ' : '\n'); W(_tail...); }
template<class T, class... U> void DB(const T &_head, const U &... _tail) {
#ifdef HOME
    W('#', _head, _tail...);
#endif
}

#define SZ(x) (int)((x).size())
#define ALL(x) (x).begin(), (x).end()
#define RAN(x,n) (x).begin(), (x).begin()+(n)
#define UNIQUE(x) {sort(ALL(x)); (x).erase(unique(ALL(x)), (x).end());}

#define REP(i,a,b) for (int i = (a); i <= (b); ++i)
#define REPD(i,a,b) for (int i = (a); i >= (b); --i)
#define FORI(i,n) REP(i,1,n)
#define FOR(i,n) REP(i,0,int(n)-1)
//#define ITER(i,t) for (auto i = t.begin(); i != t.end(); ++i)
#define IT3(i,st,ed) for (auto i = st; i != ed; ++i)
#define IT2(i,range) IT3(i,range)

#define MS0(X) memset((X), 0, sizeof((X)))
#define MS1(X) memset((X), -1, sizeof((X)))
#define MS(X, v) memset((X), (v), sizeof((X)))

template<class T> using MaxHeap = priority_queue<T>;
template<class T> using MinHeap = priority_queue<T, vector<T>, greater<T>>;

typedef int64_t ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;

inline int LG (const unsigned int &_x) { return 31-__builtin_clz(_x); }  // floor: LG(x), ceil: LG(x-1)+1
/*}}}*/

int n, k;
vector<ll> as, fs;

int main(){
    R(n, k);
    as.assign(n, 0), fs.assign(n, 0);
    FOR(i, n) R(as[i]);
    FOR(i, n) R(fs[i]);

    sort(ALL(as));
    sort(ALL(fs), [](ll a, ll b){ return a > b; });

    ll left = 0, right = 1LL << 50;
    while(left < right){
        ll mi = (left + right) / 2;

        vector<ll> gs(ALL(fs));
        FOR(i, n) gs[i] = mi / gs[i];
        ll sum = 0;
        FOR(i, n) sum += max(0LL, as[i] - gs[i]);
        bool check = sum <= k;

        if(check) right = mi;
        else left = mi + 1;
    }

    W(left);

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:88:29: error: no matching function for call to 'max(long long int, __gnu_cxx::__alloc_traits<std::allocator<long int>, long int>::value_type)'
   88 |         FOR(i, n) sum += max(0LL, as[i] - gs[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:5:
/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:88:29: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and '__gnu_cxx::__alloc_traits<std::allocator<long int>, long int>::value_type' {aka 'long int'})
   88 |         FOR(i, n) sum += max(0LL, as[i] - gs[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:88:29: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   88 |         FOR(i, n) sum += max(0LL, as[i] - gs[i]);
      |                          ~~~^~~~~~~~~~~~~~~~~~~~