Submission #780051

#	Time	Username	Problem	Language	Result	Execution time	Memory
780051		_martynas	Carnival Tickets (IOI20_tickets)	C++14	100 / 100	1000 ms	114432 KiB

tickets

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

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));
    ll sum = 0;
    struct Info {
        int val;
        int i, j, k;
        bool operator<(const Info &rhs) const {
            return make_pair(val, j) < make_pair(rhs.val, rhs.j);
        }
    };
    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);
            }
        }
    }
    priority_queue<pair<int, int>> another_pq;
    for(int i = 0; i < n; i++) {
        another_pq.push({count(answer[i].begin(), answer[i].end(), -2), i});
    }
    for(int q = 0; q < k; q++) {
        priority_queue<pair<int, int>> new_another_pq;
        for(int o = 0; o < n/2; o++) {
            int cnt = another_pq.top().F;
            int i = another_pq.top().S;
            another_pq.pop();
            answer[i][lo[i].back()] = q;
            lo[i].pop_back();
            cnt--;
            new_another_pq.push({cnt, i});
        }
        for(int o = 0; o < n/2; o++) {
            int cnt = another_pq.top().F;
            int i = another_pq.top().S;
            another_pq.pop();
            answer[i][up[i].back()] = q;
            up[i].pop_back();
            new_another_pq.push({cnt, i});
        }
        another_pq = new_another_pq;
    }
    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