Submission #838817

#	Time	Username	Problem	Language	Result	Execution time	Memory
838817		LucaIlie	Cake 3 (JOI19_cake3)	C++17	24 / 100	4035 ms	10980 KiB

cake3

#include <bits/stdc++.h>

using namespace std;

struct ab {
    int a, b;
};

struct event {
    int type, val, t;
};

int m;
const int MAX_N = 2e5;
const long long INF = 1e18;
ab v[MAX_N + 1];
int timee = 0;
long long sumA;
vector<event> events;

struct pos {
    int p;

    bool operator < ( const pos q ) const {
        if ( v[p].a == v[q.p].a )
            return p < q.p;
        return v[p].a < v[q.p].a;
    }
};

set<pos> s;

void insertt( int x ) {
    s.insert( { x } );
    sumA += v[x].a;
    events.push_back( { 1, x, ++timee } );
}

void erasee( int x ) {
    s.erase( { x } );
    sumA -= v[x].a;
    events.push_back( { -1, x, ++timee } );
}

void rollback( int t ) {
    while ( !events.empty() && events.back().t > t ) {
        int x = events.back().val;
        if (events.back().type == 1 ) {
            s.erase( { x } );
            sumA -= v[x].a;
        } else {
            s.insert( { x } );
            sumA += v[x].a;
        }
        events.pop_back();
    }
}

long long solve( int ll, int lr, int rl, int rr ) {
    if ( ll > lr || rl > rr )
        return -INF;


    int l = (ll + lr) / 2;
    long long answer = -INF;
    int bestR = rr;
    int t = timee;

    for ( int i = l; i <= lr && i < rl; i++ ) {
        insertt( { i } );
        if ( s.size() > m )
            erasee( s.begin()->p );
    }

    for ( int r = max( l, rl ); r <= rr; r++ ) {
        insertt( { r } );
        if ( s.size() > m )
            erasee( s.begin()->p );

        if ( s.size() >= m ) {
            if ( sumA - 2 * (v[r].b - v[l].b) > answer ) {
                answer = sumA - 2 * (v[r].b - v[l].b);
                bestR = r;
            }
        }
    }

    rollback( t );
    for ( int i = min( rl - 1, lr ); i >= l; i-- ) {
        insertt( { i } );
        if ( s.size() > m )
            erasee( s.begin()->p );
    }
    answer = max( answer, solve( ll, l - 1, rl, bestR ) );

    rollback( t );
    for ( int i = max( rl, lr + 1 ); i < bestR; i++ ) {
        insertt( { i } );
        if ( s.size() > m )
            erasee( s.begin()->p );
    }
    answer = max( answer, solve( l + 1, lr, bestR, rr ) );

    rollback( t );
    return answer;
}

int main() {
    int n;
    
    cin.tie( NULL );
    ios_base::sync_with_stdio( false );

    cin >> n >> m;
    for ( int i = 1; i <= n; i++ )
        cin >> v[i].a >> v[i].b;
    sort( v + 1, v + 1 + n, []( ab x, ab y ) {
        return x.b < y.b;
    } );

    cout << solve( 1, n, 1, n );

    return 0;
}

Compilation message (stderr)

cake3.cpp: In function 'long long int solve(int, int, int, int)':
cake3.cpp:71:23: warning: comparison of integer expressions of different signedness: 'std::set<pos>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   71 |         if ( s.size() > m )
      |              ~~~~~~~~~^~~
cake3.cpp:77:23: warning: comparison of integer expressions of different signedness: 'std::set<pos>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   77 |         if ( s.size() > m )
      |              ~~~~~~~~~^~~
cake3.cpp:80:23: warning: comparison of integer expressions of different signedness: 'std::set<pos>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   80 |         if ( s.size() >= m ) {
      |              ~~~~~~~~~^~~~
cake3.cpp:91:23: warning: comparison of integer expressions of different signedness: 'std::set<pos>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   91 |         if ( s.size() > m )
      |              ~~~~~~~~~^~~
cake3.cpp:99:23: warning: comparison of integer expressions of different signedness: 'std::set<pos>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   99 |         if ( s.size() > m )
      |              ~~~~~~~~~^~~

• Subtask 1: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 0 / 76