Submission #657292

#	Time	Username	Problem	Language	Result	Execution time	Memory
657292		600Mihnea	Fun Tour (APIO20_fun)	C++17	26 / 100	14 ms	388 KiB

fun

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

using namespace std;

vector<int> createFunTourForSubtasks1and2(int n, int q) {
	vector<vector<int>> g(n);
	int cnt_edges = 0;
	for (int i = 0; i < n; i++) {
		for (int j = i + 1; j < n; j++) {
			if (hoursRequired(i, j) == 1) {
				g[i].push_back(j);
				g[j].push_back(i);
				cnt_edges++;
			}
		}
	}
	assert(cnt_edges == n - 1);
	
	vector<bool> active(n, 1);
	vector<int> dist(n, -1);
	
	function<int(int)> find_far = [&] (int root) {
		assert(active[root]);
		queue<int> q;
		
		for (int i = 0; i < n; i++) {
			dist[i] = -1;
		}
		
		dist[root] = 0;
		q.push(root);
		
		while (!q.empty()) {
			int a = q.front();
			q.pop();
			for (auto &b : g[a]) {
				if (active[b] && dist[b] == -1) {
					dist[b] = 1 + dist[a];
					q.push(b);
				}
			}
		}
		int sol = root;
		for (int i = 0; i < n; i++) {
			if (dist[i] > dist[sol]) {
				sol = i;
			}
		}
		return sol;
	};
	
	vector<int> ord;
	ord.push_back(find_far(0));
	for (int step = 2; step <= n; step++) {
		int nw = find_far(ord.back());
		active[ord.back()] = 0;
		ord.push_back(nw);
	}
	assert((int) ord.size() == n);
	return ord;
}

vector<int> createFunTour(int n, int q) {
	if (n <= 500) {
		return createFunTourForSubtasks1and2(n, q);
	}
	return {};
}

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 0 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 34