Submission #983918

#	Time	Username	Problem	Language	Result	Execution time	Memory
983918		phoenix0423	Carnival Tickets (IOI20_tickets)	C++17	27 / 100	417 ms	51468 KiB

tickets

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define pb push_back
#define eb emplace_back
#include "tickets.h"
const int maxn = 1505;
const ll INF = 1e18;
ll dp[maxn][maxn];

long long find_maximum(int k, std::vector<std::vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
	vector<vector<int>> ans(n, vector<int>(m, -1));
	ll cost = 0;
	multiset<pll> stl, str; // l : l -> r, r : r -> l
	vector<int> l(n), r(n);
	auto rid = [&](int i) -> void {
		if(l[i]) stl.erase({x[i][r[i]] + x[i][l[i] - 1], i});
		if(r[i] < m - 1) str.erase({x[i][r[i] + 1] + x[i][l[i]], i});
	};
	auto put = [&](int i) -> void {
		if(l[i]) stl.insert({x[i][r[i]] + x[i][l[i] - 1], i});
		if(r[i] < m - 1) str.insert({x[i][r[i] + 1] + x[i][l[i]], i});
	};
	for(int i = 0; i < n; i++){
		if(i < n / 2) l[i] = k, r[i] = m - 1;
		else l[i] = 0, r[i] = m - 1 - k;
		int cnt = 0;
		for(int j = 0; j < l[i]; j++) cost -= x[i][j], ans[i][j] = cnt++;
		cnt = k - 1;
		for(int j = r[i] + 1; j < m; j++) cost += x[i][j], ans[i][j] = cnt--;
		put(i);
	}
	while(true){
		// spfa? dijkstra?
		auto [a, b] = *prev(stl.end());
		auto [c, d] = *str.begin();
		if(b == d || a < c) break;
		// cout<<"cur : "<<b<<" : "<<a<<", "<<d<<" : "<<c<<"\n";
		// cout<<l[b]<<" "<<r[b]<<" "<<l[d]<<" "<<r[d]<<"\n";
		cost += a - c;
		rid(b), rid(d);
		// stl.erase(prev(stl.end()));
		// str.erase(str.begin());
		swap(ans[b][l[b] - 1], ans[b][r[b]]);
		swap(ans[d][l[d]], ans[d][r[d] + 1]);
		l[b] --, r[b] --;
		l[d] ++, r[d] ++;
		put(b), put(d);
	}
	// cout<<"c : "<<cost<<"\n";
	allocate_tickets(ans);
	return cost;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10