Submission #974596

#	Time	Username	Problem	Language	Result	Execution time	Memory
974596		LucaIlie	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	706 ms	127596 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>

using namespace std;

struct cell {
    int i, j, val;
};

const int MAX_N = 1500;
const int MAX_M = 1500;
int x[MAX_N + 1][MAX_M + 1], l[MAX_N];
long long sx[MAX_N + 1][MAX_M + 1];
vector<int> mins[MAX_N + 1], maxs[MAX_N + 1];
vector<cell> opt;

long long find_maximum( int k, vector<vector<int>> X ) {
    int n = X.size();
    int m = X[0].size();
    vector<vector<int>> answer( n );
    long long sum = 0;

    for ( int i = 1; i <= n; i++ ) {
        answer[i - 1].resize( m );
        for ( int j = 1; j <= m; j++ ) {
            x[i][j] = X[i - 1][j - 1];
            sx[i][j] = sx[i][j - 1] + x[i][j];
            answer[i - 1][j - 1] = -1;
        }
    }

    for ( int i = 1; i <= n; i++ ) {
        for ( int j = 1; j <= k; j++ ) {
            mins[i].push_back( j );
            opt.push_back( { i, m - (k - j), x[i][j] + x[i][m - (k - j)] } );
        }
    }

    sort( opt.begin(), opt.end(), []( cell a, cell b ) {
        if ( a.val == b.val )
            return a.j > b.j;
        return a.val > b.val;
    } );
    for ( int i = 0; i < n * k / 2; i++ ) {
        mins[opt[i].i].pop_back();
        maxs[opt[i].i].push_back( opt[i].j );
    }

    for ( int i = 1; i <= n; i++ ) {
        reverse( maxs[i].begin(), maxs[i].end());

        vector<pair<int, int>> pasi;
        for ( int pas = 0; pas < k; pas++ )
            pasi.push_back( { l[pas], pas } );
        sort( pasi.begin(), pasi.end() );

        int ind = 0;
        for ( int j: mins[i] ) {
            answer[i - 1][j - 1] = pasi[ind].second;
            l[pasi[ind].second]++;
            sum -= x[i][j];
            ind++;
        }
        for ( int j: maxs[i] ) {
            answer[i - 1][j - 1] = pasi[ind].second;
            sum += x[i][j];
            ind++;
        }
    }

    allocate_tickets( answer );
    return sum;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 14 / 14
• Subtask 4: 14 / 14
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23
• Subtask 7: 10 / 10