Submission #1059309

#	Time	Username	Problem	Language	Result	Execution time	Memory
1059309		esomer	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	463 ms	76284 KiB

tickets

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

using namespace std;

typedef long long ll;

int n, m, k;
set<pair<int, int>> add0, add1;

void Add0(int i, vector<int>& zeros, vector<int>& ones, vector<vector<int>>& x){
	if(zeros[i] < k) add0.insert({x[i][zeros[i]] + x[i][m-ones[i]], i});
}

void Add1(int i, vector<int>& zeros, vector<int>& ones, vector<vector<int>>& x){
	if(zeros[i] > 0) add1.insert({x[i][zeros[i]-1] + x[i][m-ones[i]-1], i});
}

void Erase0(int i, vector<int>& zeros, vector<int>& ones, vector<vector<int>>& x){
	if(zeros[i] < k) add0.erase({x[i][zeros[i]] + x[i][m-ones[i]], i});
}

void Erase1(int i, vector<int>& zeros, vector<int>& ones, vector<vector<int>>& x){
	if(zeros[i] > 0) add1.erase({x[i][zeros[i]-1] + x[i][m-ones[i]-1], i});
}

long long find_maximum(int _k, vector<vector<int>> x) {
	k = _k;
	n = (int)x.size();
	m = (int)x[0].size();
	vector<int> zeros(n, k/2), ones(n, k - k/2);
	add0.clear(); add1.clear();
	for(int i = 0; i < n; i++){
		if(i%2 && k%2) {zeros[i]++; ones[i]--;}
		//To convert 1 to 0, I substract the sum of both.
		//To convert 0 to 1, I add the sum of both.
		Add0(i, zeros, ones, x);
		Add1(i, zeros, ones, x);
		//If I already have chosen k, it is the same element that I am adding twice.
	}
	//So, at each time, I convert one from 0 to 1 and one from 1 to 0. The ones from 1 to 0 I substract.
	while((*add1.rbegin()).first - (*add0.begin()).first > 0){
		int ind1 = (*add1.rbegin()).second; add1.erase(*add1.rbegin());
		int ind0 = (*add0.begin()).second; add0.erase(add0.begin());
		Erase0(ind1, zeros, ones, x);
		Erase1(ind0, zeros, ones, x);
		zeros[ind1]--; ones[ind1]++; zeros[ind0]++; ones[ind0]--;
		Add0(ind0, zeros, ones, x);
		Add1(ind0, zeros, ones, x);
		Add0(ind1, zeros, ones, x);
		Add1(ind1, zeros, ones, x);
	}
	ll res = 0;
	for(int i = 0; i < n; i++){
		// cout << "i " << i << " zeros " << zeros[i] << " ones " << ones[i] << "\n";
		for(int j = 0; j < zeros[i]; j++) res -= x[i][j];
		for(int j = m - ones[i]; j < m; j++) res += x[i][j];
	}
	vector<vector<int>> ans(n, vector<int>(m, -1));
	vector<pair<int, int>> rng(n);
	for(int i = 0; i < n; i++){
		rng[i] = {zeros[i]-1, m-1}; //The starting index from which I go down for each of them.
	}
	for(int r = 0; r < k; r++){
		vector<pair<int, int>> ordOne(n);
		for(int i = 0; i < n; i++){
			ordOne[i] = {ones[i], i};
		}
		sort(ordOne.begin(), ordOne.end());
		for(int i = n/2; i < n; i++){
			int row = ordOne[i].second;
			ones[row]--; 
			ans[row][rng[row].second] = r;
			rng[row].second--;
		}
		for(int i = 0; i < n/2; i++){
			int row = ordOne[i].second;
			zeros[row]--;
			ans[row][rng[row].first] = r;
			rng[row].first--;
		}
	}
	allocate_tickets(ans);
	return res;
}

• 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