Submission #779715

#	Time	Username	Problem	Language	Result	Execution time	Memory
779715		_martynas	Carnival Tickets (IOI20_tickets)	C++14	27 / 100	389 ms	51696 KiB

tickets

#include "tickets.h"
#include <vector>
#include <cmath>
#include <algorithm>
#include <queue>
#include <iostream>

using namespace std;

#define F first
#define S second
#define PB push_back

using ll = long long;

// each vector<int> in x is sorted
long long find_maximum(int k, vector<vector<int>> x) {
	/* sample interaction
	int n = x.size();
	int m = x[0].size();
	vector<vector<int>> answer;
	for (int i = 0; i < n; i++) {
		vector<int> row(m);
		for (int j = 0; j < m; j++) {
			if (j < k) {
				row[j] = j;
			} else {
				row[j] = -1;
			}
		}
		answer.push_back(row);
	}
	allocate_tickets(answer);
	return 1;
	*/
	int n = x.size();
	int m = x[0].size();
	vector<vector<int>> answer(n, vector<int>(m, -1));
    // same sol as subtask 2 but all values all at once
    ll sum = 0;
    struct Info {
        int val;
        int i, j, k;
        bool operator<(const Info &rhs) const {
            return val < rhs.val;
        }
    };
    priority_queue<Info> pq;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < k; j++) {
            answer[i][j] = -2; // lower half
            int jj = m-k+j;
            sum -= x[i][j];
            pq.push({x[i][j]+x[i][jj], i, j, jj});
        }
    }
    for(int i = 0; i < k*n/2; i++) {
        answer[pq.top().i][pq.top().j] = -1;
        answer[pq.top().i][pq.top().k] = -3; // upper half
        sum += pq.top().val;
        pq.pop();
    }
    vector<vector<int>> lo(n), up(n);
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            if(answer[i][j] == -2) {
                lo[i].PB(j);
            }
            else if(answer[i][j] == -3) {
                up[i].PB(j);
            }
        }
    }
    for(int q = 0; q < k; q++) {
        int cnt = n/2;
        vector<bool> skip(n);
        for(int i = 0; i < n && cnt; i++) {
            if(lo[i].size()) {
                skip[i] = true;
                answer[i][lo[i].back()] = q;
                lo[i].pop_back();
                cnt--;
            }
        }
        for(int i = 0; i < n; i++) {
            if(!skip[i] && up[i].size()) {
                answer[i][up[i].back()] = q;
                up[i].pop_back();
            }
        }
    }
    allocate_tickets(answer);
    return sum;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10