Submission #779671

#	Time	Username	Problem	Language	Result	Execution time	Memory
779671		_martynas	Carnival Tickets (IOI20_tickets)	C++14	27 / 100	2317 ms	57044 KiB

tickets

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

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));
	if(m == 1) {
        // subtask 1 (only a single way to pick everything)
        vector<int> A;
        for(int i = 0; i < n; i++) {
            A.PB(x[i][0]);
            answer[i][0] = 0;
        }
        sort(A.begin(), A.end());
        ll sum = 0;
        for(int a : A) {
            sum += abs(a-A[n/2]);
        }
        allocate_tickets(answer);
        return sum;
	}
	else {
        // same sol as subtask 2 but repeat k times
        ll sum = 0;
        struct Info {
            int val;
            int i, j, k;
            bool operator<(const Info &rhs) const {
                return val < rhs.val;
            }
        };
        for(int q = 0; q < k; q++) {
            priority_queue<Info> pq;
            for(int i = 0; i < n; i++) {
                int l = -1, r = -1;
                for(int j = 0; j < m; j++) {
                    if(answer[i][j] != -1) continue;
                    if(l == -1) l = j;
                    r = j;
                }
                answer[i][l] = q;
                sum -= x[i][l];
                pq.push({x[i][l]+x[i][r], i, l, r});
            }
            for(int i = 0; i < n/2; i++) {
                answer[pq.top().i][pq.top().j] = -1;
                answer[pq.top().i][pq.top().k] = q;
                sum += pq.top().val;
                pq.pop();
            }
        }
        allocate_tickets(answer);
        return sum;
	}
	allocate_tickets(answer);
	return -1;
}

• 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