Submission #1000080

#	Time	Username	Problem	Language	Result	Execution time	Memory
1000080		phoenix	Carnival Tickets (IOI20_tickets)	C++17	11 / 100	1 ms	860 KiB

tickets

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

using namespace std;

long long func(vector<int> a) {
	sort(a.begin(), a.end());
	long long ans = 0;
	for (int i = 0; i < (int)a.size(); i++) {
		ans += (i * 2 < (int)a.size() ? -1 : +1) * a[i];
	}
	return ans;
}

long long find_maximum(int k, vector<vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
	vector<vector<int>> answer(n, vector<int>(m, -1));
	vector<int> l(n, 0), r(n, m - 1);
	
	long long ans = 0;
	for (int iter = 0; iter < k; iter++) {
		vector<pair<int, int>> v1, v2;
		for (int i = 0; i < n; i++) {
			v1.push_back({x[i][l[i]], i});
			v2.push_back({x[i][r[i]], i});
		}
		sort(v1.begin(), v1.end());
		sort(v2.begin(), v2.end());
		vector<int> b1(n), b2(n);
		for (int i = 0; i < n; i++) {
			int cl;
			cl = v1[i].second;
			b1[i] = (i * 2 < n ? x[cl][l[cl]] : x[cl][r[cl]]);
			cl = v2[i].second;
			b2[i] = (i * 2 < n ? x[cl][l[cl]] : x[cl][r[cl]]);
		}
		if (func(b1) >= func(b2)) {
			ans += func(b1);
			for (int i = 0; i < n; i++) {
				int cl = v1[i].second;
				if (i * 2 < n) {
					answer[cl][l[cl]] = iter;
					l[cl]++;
				}
				else {
					answer[cl][r[cl]] = iter;
					r[cl]--;
				}
			}
		} else {
			ans += func(b2);
			for (int i = 0; i < n; i++) {
				int cl = v2[i].second;
				if (i * 2 < n) {
					answer[cl][l[cl]] = iter;
					l[cl]++;
				} else {
					answer[cl][r[cl]] = iter;
					r[cl]--;
				}
			}
		}
	}
	
	allocate_tickets(answer);
	return ans;
}

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