Submission #435681

#	Time	Username	Problem	Language	Result	Execution time	Memory
435681		BERNARB01	Fountain Parks (IOI21_parks)	C++17	15 / 100	321 ms	43336 KiB

parks

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

using namespace std;

int construct_roads(vector<int> x, vector<int> y) {
	if (x.size() == 1) {
		build({}, {}, {}, {});
		return 1;
	}
	int n = x.size();
	vector<pair<int, int>> p2, p4;
	for (int i = 0; i < n; i++) {
		if (x[i] == 2) {
			p2.emplace_back(y[i], i);
		} else if (x[i] == 4) {
			p4.emplace_back(y[i], i);
		}
	}
	sort(p2.begin(), p2.end());
	sort(p4.begin(), p4.end());
	vector<int> u, v, a, b;
	for (int j = 1; j < (int) p2.size(); j++) {
		int i = p2[j].second;
		int k = p2[j - 1].second;
		if (y[i] - y[k] > 2) {
			continue;
		}
		u.push_back(k);
		v.push_back(i);
		a.push_back(1);
		b.push_back(y[i] - 1);
	}
	for (int j = 1; j < (int) p4.size(); j++) {
		int i = p4[j].second;
		int k = p4[j - 1].second;
		if (y[i] - y[k] > 2) {
			continue;
		}
		u.push_back(k);
		v.push_back(i);
		a.push_back(5);
		b.push_back(y[i] - 1);
	}
	for (int i = 0, j = 0; i < (int) p2.size(); i++) {
		while (j < (int) p4.size() && p4[j].first < p2[i].first) {
			j++;
		}
		if (j >= (int) p4.size()) {
			break;
		}
		if (p2[i].first == p4[j].first) {
			int ii = p2[i].second;
			int jj = p4[j].second;
			u.push_back(ii);
			v.push_back(jj);
			a.push_back(3);
			b.push_back(y[ii] - 1);
		}
	}
	auto dist = [&](int i, int j) {
		return (x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]);
	};
	vector<vector<int>> g(n);
	for (int i = 0; i < (int) u.size(); i++) {
		if (dist(u[i], v[i]) > 4) {
			return 0;
		}
		g[u[i]].push_back(v[i]);
		g[v[i]].push_back(u[i]);
	}
	vector<int> vis(n, 0);
	function<void(int)> dfs = [&](int uu) {
		if (vis[uu]) {
			return;
		}
		vis[uu] = 1;
		for (int vv : g[uu]) {
			dfs(vv);
		}
	};
	dfs(0);
	if (accumulate(vis.begin(), vis.end(), 0) == n) {
		build(u, v, a, b);
		return 1;
	}
	return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30