Submission #420495

#	Time	Username	Problem	Language	Result	Execution time	Memory
420495		Mazaalai	Carnival Tickets (IOI20_tickets)	C++14	0 / 100	1 ms	288 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair <int, int> PII;
#define ff first
#define ss second

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> hiIdx(n, m-1), used(n, 0);
	vector <int> loIdx(n, 0);
	set <PII> hiVal, loVal; // val, idx;
	for (int i = 0; i < n; i++) {
		hiVal.insert({-x[i][hiIdx[i]], i});
		loVal.insert({x[i][loIdx[i]], i});
	}
	ll cnt = 0, ans = 0;
	vector <vector <PII> > pairs;
	while(cnt < n * k) {
		// max1, max2, min1, min2
		while(used[(hiVal.begin())->ss] >= k) 
			hiVal.erase(hiVal.begin());
		while(used[(loVal.begin())->ss] >= k) 
			loVal.erase(loVal.begin());
		
		auto itMax1 = hiVal.begin();
		auto itMin1 = loVal.begin();
		PII max1 = *itMax1, max2;
		PII min1 = *itMin1, min2;
		int a, b;
		if (max1.ss != min1.ss) {
			a = max1.ss;
			b = min1.ss;
			hiVal.erase(max1);
			loVal.erase(min1);
		} else {
			while(used[(++hiVal.begin())->ss] >= k) 
				hiVal.erase(++hiVal.begin());
			while(used[(++loVal.begin())->ss] >= k) 
				loVal.erase(++loVal.begin());
			max2 = *(++itMax1);
			min2 = *(++itMin1);
			if (-max1.ff - min2.ff >= -max2.ff - min1.ff) {
				a = max1.ss;
				b = min2.ss;
				hiVal.erase(max1);
				loVal.erase(min2);
			} else {
				a = max2.ss;
				b = min1.ss;
				hiVal.erase(max2);
				loVal.erase(min1);
			}
		}
		ll dif = abs(x[a][hiIdx[a]] - x[b][loIdx[b]]);
		max1 = {a, hiIdx[a]};
		min1 = {b, loIdx[b]};
		pairs.push_back({max1, min1});
		ans += dif;
		hiVal.insert({-x[a][--hiIdx[a]], a});
		loVal.insert({x[b][++loIdx[b]], b});
		cnt += 2;
	}
	// vector <vector <bool> > used(n, vector <bool> (m, 0));
	vector <set <int> > pickSets(n);
	for (int i = 0; i < n; i++) 
	for (int j = 0; j < k; j++) pickSets[i].insert(j);
	for (auto el : pairs) {
		// for (auto )
		int a1, a2, b1, b2;
		tie(a1, a2) = el[0];
		tie(b1, b2) = el[1];
		// cout << a1 << ',' << a2 << ' ' << b1 << ',' << b2 << '\n';
		// cout << "A: ";
		// for (auto el : pickSets[a1]) cout << el << ' ';
		// cout << "\n";
		// cout << "B: ";
		// for (auto el : pickSets[b1]) cout << el << ' ';
		// cout << "\n";
		for (auto pos : pickSets[a1]) {
			auto it = pickSets[b1].lower_bound(pos);
			if (it == pickSets[b1].end() || *it != pos) continue;
			pickSets[a1].erase(pos);
			pickSets[b1].erase(pos);
			answer[a1][a2] = answer[b1][b2] = pos;
			break;
		}
		// cout << el[0].ff << ',' << el[0].ss << ' ' << el[1].ff << ',' << el[1].ss << '\n';
	}

	allocate_tickets(answer);
	return ans;
}

• Subtask 1: 0 / 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