Submission #736896

#	Time	Username	Problem	Language	Result	Execution time	Memory
736896		sentheta	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	689 ms	97060 KiB

tickets

#include "tickets.h"
// author : sentheta aka vanwij
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<cassert>
#include<random>
#include<chrono>
#include<cmath>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<stack>
#include<map>
#include<set>
using namespace std;

#define Int long long
#define V vector
#define pii pair<Int,Int>
#define ff first
#define ss second

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

#define pow2(x) (1LL<<(x))
#define msb(x) (63-__builtin_clzll(x))
#define bitcnt(x) (__builtin_popcountll(x))

#define nl '\n'
#define _ << ' ' <<
#define all(x) (x).begin(), (x).end()
#define rep(i,a,b) for(int i = (int)(a); i < (int)(b); i++)
#define dbg(x) if(1) cout << "?" << #x << " : " << (x) << endl << flush;

const int N = 1505;

Int n, m, k;
V<V<int>> a;

Int sum = 0;
V<V<int>> ans;

V<int> sneg[N], unused[N];

// count of pos for each color
Int poscnt[N];

// pointer to next positive/negative
Int posptr[N], negptr[N];

Int find_maximum(int _k,V<V<int>> _a){
	a.swap(_a);
	n = a.size(); m = a[0].size(); k = _k;
	
	// {delta, color}
	priority_queue<pii> pq;
	rep(i,0,n){
		posptr[i] = m-1;
		negptr[i] = 0;

		rep(j,0,k){
			sneg[i].push_back(a[i][j]);
			sum -= a[i][j];
		}
		unused[i] = a[i];

		pq.push({0LL+unused[i].back()+sneg[i].back(), i});
	}

	// change n*k/2 cards to pos
	rep(loop,0,n*k/2){
		auto[delta,i] = pq.top(); pq.pop();
		sneg[i].pop_back();
		unused[i].pop_back();

		sum += delta;
		poscnt[i]++;
		if(!sneg[i].empty()){
			pq.push({unused[i].back()+sneg[i].back(), i});
		}
	}

	// assign answer
	ans = V<V<int>>(n,V<int>(m,-1));
	rep(t,0,k){
		V<int> ord(n);
		rep(i,0,n) ord[i] = i;
		sort(all(ord),[&](int i,int j){
			return poscnt[i] < poscnt[j];
		});

		// assign negative
		rep(ii,0,n/2){
			int i = ord[ii];
			ans[i][negptr[i]++] = t;
		}
		// assign positive
		rep(ii,n/2,n){
			int i = ord[ii];
			ans[i][posptr[i]--] = t;
			poscnt[i]--;
		}
	}


	allocate_tickets(ans);
	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