Submission #557202

#	Time	Username	Problem	Language	Result	Execution time	Memory
557202		czhang2718	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	1128 ms	132848 KiB

tickets

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

using namespace std;

#define rep(i,a,b) for(int i=a; i<=b; i++)
#define all(x) x.begin(),x.end()
#define sz(x) int(x.size())
#define pb push_back
typedef vector<int> vi;
typedef pair<int,int> pii;
#define f first
#define s second

const int N=1501;
bool use[N][N];

long long find_maximum(int k, std::vector<std::vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
	std::vector<std::vector<int>> answer;
	for (int i = 0; i < n; i++) {
		std::vector<int> row(m, -1);
		answer.push_back(row);
	}

	vector<int> cnt(n);
	vector<pii> inc;
	rep(i,0,n-1){
		rep(j,0,k-1){
			inc.pb({x[i][m-1-j]+x[i][k-1-j], i});
			use[i][j]=1;
		}
	}
	sort(all(inc), greater<pii>());

	rep(t,1,n*k/2){
		auto p=inc[t-1];
		// cout << "switch " << p.s << " " << k-1-cnt[p.s] << "->" << m-1-cnt[p.s] << '\n';
		use[p.s][k-1-cnt[p.s]]=0;
		use[p.s][m-1-cnt[p.s]]=1;
		cnt[p.s]++;
	}

	vector<pair<int, pii>> vec;
	rep(i,0,n-1) rep(j,0,m-1){
		if(use[i][j]) vec.pb({x[i][j], {i,j}});
	}
	sort(all(vec));
	long long sum=0;
	rep(i,1,n*k){
		if(i<=n*k/2) sum-=vec[i-1].f;
		else sum+=vec[i-1].f;
	}
	auto L=vec[n*k/2];

	vector<vi> big(n), small(n);
	vi v[3];
	rep(i,0,n-1){
		rep(j,0,m-1){
			if(!use[i][j]) continue;
			if(make_pair(x[i][j], make_pair(i,j))>=L) big[i].pb(j);
			else small[i].pb(j);
		}
		if(sz(big[i]) && sz(small[i])) v[2].pb(i);
		else if(sz(big[i])) v[1].pb(i);
		else v[0].pb(i);
	}

	rep(t,0,k-1){
		int a=0, b=0;
		vi put_back;

		// small
		int A=sz(v[0]);
		rep(i,1,min(A,n/2)){
			a++;
			int j=v[0].back();
			v[0].pop_back();
			answer[j][small[j].back()]=t;
			small[j].pop_back();
			if(sz(small[j])) put_back.pb(j);
		}
		for(int i:put_back) v[0].pb(i);

		// big
		put_back.clear();
		int B=sz(v[1]);
		rep(i,1,min(B,n/2)){
			b++;
			int j=v[1].back();
			v[1].pop_back();
			answer[j][big[j].back()]=t;
			big[j].pop_back();
			if(sz(big[j])) put_back.pb(j);
		}
		for(int i:put_back) v[1].pb(i);

		// both
		put_back.clear();
		rep(i,1,n/2-a){
			int j=v[2].back();
			v[2].pop_back();
			answer[j][small[j].back()]=t;
			small[j].pop_back();
			if(sz(small[j]) && sz(big[j])) put_back.pb(j);
			else if(sz(small[j])) v[0].pb(j);
			else v[1].pb(j);
		}

		rep(i,1,n/2-b){
			int j=v[2].back();
			v[2].pop_back();
			answer[j][big[j].back()]=t;
			big[j].pop_back();
			if(sz(small[j]) && sz(big[j])) put_back.pb(j);
			else if(sz(small[j])) v[0].pb(j);
			else v[1].pb(j);
		}
		for(int i:put_back) v[2].pb(i);
	}

	allocate_tickets(answer);
	return sum;
}
// dont know what to do without you

• 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