Submission #430206

#	Time	Username	Problem	Language	Result	Execution time	Memory
430206		pliam	Carnival Tickets (IOI20_tickets)	C++14	100 / 100	1433 ms	118208 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define MAXN 1505
#define MAXM 1505

ll ans;
int type[MAXN][MAXM];//0=unused,-1='-',1='+'
int val[MAXN][MAXM];
priority_queue<int> q_col_minus[MAXN];//by color -> pos
priority_queue<int> q_col_unused[MAXN];
priority_queue<pair<ll,int>> q_gen;//general -> (num,col)
vector<vector<int>> answer;
vector<int> plus_[MAXN];
vector<int> minus_[MAXN];

bool changeable(int col){
	return !q_col_minus[col].empty();
}

ll res(int col){
	if(q_col_unused[col].empty()) return 2*val[col][q_col_minus[col].top()];
	else return val[col][q_col_minus[col].top()]+val[col][max(q_col_unused[col].top(),q_col_minus[col].top())];
}

void change(int col){
	ans+=res(col);
	if(q_col_unused[col].empty()){
		int pos=q_col_minus[col].top();
		q_col_minus[col].pop();
		type[col][pos]=1;
	}else{
		int pos_minus=q_col_minus[col].top();
		int pos_unused=q_col_unused[col].top();
		if(pos_minus<pos_unused){
			q_col_minus[col].pop();
			q_col_unused[col].pop();
			type[col][pos_minus]=0;
			q_col_unused[col].push(pos_minus);
			type[col][pos_unused]=1;
		}else{
			q_col_minus[col].pop();
			type[col][pos_minus]=1;
		}
	}
	q_gen.pop();
	if(changeable(col)) q_gen.push({res(col),col});
}

ll find_maximum(int k, vector<vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
	ans=0;
	for(int col=0;col<n;col++){
		answer.push_back(vector<int>(m,-1));
		for(int pos=0;pos<m;pos++){
			val[col][pos]=x[col][pos];
			if(pos<k){
				q_col_minus[col].push(pos);
				type[col][pos]=-1;
				ans-=val[col][pos];
			}
			else{
				q_col_unused[col].push(pos);
				type[col][pos]=0;
			}
		}
		if(changeable(col)) q_gen.push({res(col),col});
	}
	
	for(int round=0;round<k*n/2;round++){//rounds in greedy algorithm
		change(q_gen.top().second);
	}

	for(int col=0;col<n;col++){
		for(int pos=0;pos<m;pos++){
			if(type[col][pos]==1) plus_[col].push_back(pos);
			else if(type[col][pos]==-1) minus_[col].push_back(pos);
		}
	}

	for(int round=0;round<k;round++){
		vector<pair<int,int>> pluses;
		for(int col=0;col<n;col++){
			pluses.push_back({plus_[col].size(),col});
		}
		sort(pluses.begin(),pluses.end(),greater<pair<int,int>>());
		for(int i=0;i<n;i++){
			int col=pluses[i].second;
			if(i<n/2){
				answer[col][plus_[col].back()]=round;
				plus_[col].pop_back();
			}else{
				answer[col][minus_[col].back()]=round;
				minus_[col].pop_back();
			}
		}
	}
	allocate_tickets(answer);
	return ans;
}

• 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