Submission #493647

#	Time	Username	Problem	Language	Result	Execution time	Memory
493647		blue	Cake 3 (JOI19_cake3)	C++17	100 / 100	3250 ms	16616 KiB

cake3

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;
 
struct piece
{
    long long V;
    long long C;
};
 
bool operator < (piece A, piece B)
{
    return A.C < B.C;
}
 
long long res = -1'000'000'000'000'000'000LL;
 
int N, M;
vector<piece> P;
 
int L;
int R; //exclusive endpoints
multiset<long long> high_values;
multiset<long long> low_values;
long long high_values_sum;
 
void insert_to_set(long long insert_value)
{
    high_values.insert(insert_value);
    high_values_sum += insert_value;
 
    if(high_values.size() > M-2)
    {
        high_values_sum -= *high_values.begin();
        low_values.insert(*high_values.begin());
        high_values.erase(high_values.find(*high_values.begin()));
    }
}
 
void expand_left()
{
    L--;
    insert_to_set(P[L+1].V);
}
 
void expand_right()
{
    R++;
    insert_to_set(P[R-1].V);
}
 
void contract_left()
{
    long long remove_value = P[L+1].V;
    L++;
    if(low_values.find(remove_value) != low_values.end())
    {
        low_values.erase(low_values.find(remove_value));
    }
    else
    {
        high_values.erase(high_values.find(remove_value));
        high_values_sum -= remove_value;
 
        if(high_values.size() < M-2 && low_values.size() >= 1)
        {
            high_values_sum += *low_values.rbegin();
            high_values.insert(*low_values.rbegin());
            low_values.erase(low_values.find(*low_values.rbegin()));
        }
    }
}
 
void contract_right()
{
    // cerr << "contract right\n";
    // cerr << "original R = " << R << '\n';
    long long remove_value = P[R-1].V;
    R--;
    if(low_values.find(remove_value) != low_values.end())
    {
        // cerr << "case 1 entered\n";
        low_values.erase(low_values.find(remove_value));
        // cerr << "case 1 successful\n";
    }
    else
    {
        // cerr << "case 2 entered\n";
        // cerr << remove_value << '\n';
        // for(long long h: high_values) cerr << h << ' ';
        // cerr << '\n';
        high_values.erase(high_values.find(remove_value));
        high_values_sum -= remove_value;
        // cerr << "X\n";
 
        if(high_values.size() < M-2 && low_values.size() >= 1)
        {
            high_values_sum += *low_values.rbegin();
            high_values.insert(*low_values.rbegin());
            low_values.erase(low_values.find(*low_values.rbegin()));
        }
        // cerr << "case 2 successful\n";
    }
}
 
 
 
long long get_curr_score()
{
    // cerr << "\n\n";
    // cerr << L << ' ' << R << ' ' << ' ' << P[L].V + high_values_sum + P[R].V  -  2*(P[R].C - P[L].C) << '\n';
    // cerr << P[L].V << ' ' << P[R].V << ' ' << P[L].C << ' ' << P[R].C << '\n';
    // cerr << "H: ";
    // for(long long h: high_values) cerr << h << ' ';
    // cerr << "\n";
    return P[L].V + high_values_sum + P[R].V  -  2*(P[R].C - P[L].C);
}
 
 
void solve(int l1, int l2, int r1, int r2)
{
    int l = (l1+l2)/2;
 
    // cerr << "\n\n\n";
    // cerr << "solve " << l1 << ' ' << l2 << ' ' << r1 << ' ' << r2 << '\n';
    // cerr << "l = " << l << '\n';
 
    while(l < L)
        expand_left();
 
    // cerr << "A\n";
 
    while(R < max(r1, l+M-1))
        expand_right();
// cerr << "B\n";
    while(L < l)
        contract_left();
// cerr << "C\n";
    // cerr << r1 << ' ' << l << ' ' << M << ' ' << l+M-1 << ' ' << R << '\n';
    while(max(r1, l+M-1) < R)
        contract_right();
 
    // cerr << "D\n";
 
    // cerr << "L, R = " << L << ' ' << R << '\n';
 
    int bestR = R;
    long long best_score = get_curr_score();
 
    while(R+1 <= r2)
    {
        // cerr << "! ";
        // cerr << R << ' ' << r2 << '\n';
        expand_right();
        if(get_curr_score() > best_score)
        {
            best_score = get_curr_score();
            bestR = R;
        }
    }
 
    // cerr << l << ' ' << bestR << ' ' << best_score << '\n';
 
    res = max(res, best_score);
    if(l1 <= l-1)
        solve(l1, l-1, r1, bestR);
    if(l+1 <= l2)
        solve(l+1, l2, bestR, r2);
}
 
int main()
{ ios_base::sync_with_stdio(false);cin.tie(NULL);
  
    cin >> N >> M;
    P = vector<piece>(N);
    for(int i = 0; i < N; i++) cin >> P[i].V >> P[i].C;
    sort(P.begin(), P.end());
 
    L = 0;
    R = 1;
 
    solve(0, N-M, M-1, N-1);
 
    cout << res << '\n';
}

Compilation message (stderr)

cake3.cpp: In function 'void insert_to_set(long long int)':
cake3.cpp:34:27: warning: comparison of integer expressions of different signedness: 'std::multiset<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   34 |     if(high_values.size() > M-2)
      |        ~~~~~~~~~~~~~~~~~~~^~~~~
cake3.cpp: In function 'void contract_left()':
cake3.cpp:67:31: warning: comparison of integer expressions of different signedness: 'std::multiset<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   67 |         if(high_values.size() < M-2 && low_values.size() >= 1)
      |            ~~~~~~~~~~~~~~~~~~~^~~~~
cake3.cpp: In function 'void contract_right()':
cake3.cpp:98:31: warning: comparison of integer expressions of different signedness: 'std::multiset<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   98 |         if(high_values.size() < M-2 && low_values.size() >= 1)
      |            ~~~~~~~~~~~~~~~~~~~^~~~~

• Subtask 1: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 76 / 76