Submission #768176

#	Time	Username	Problem	Language	Result	Execution time	Memory
768176		green_gold_dog	Cyberland (APIO23_cyberland)	C++17	100 / 100	1889 ms	23796 KiB

cyberland

#include "cyberland.h"

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll INF = 1'000'000'000'000'000'000;

void dfs(ll v, ll h, vector<vector<pair<ll, ll>>>& g, vector<bool>& used) {
	used[v] = true;
	if (v == h) {
		return;
	}
	for (auto[i, _] : g[v]) {
		if (!used[i]) {
			dfs(i, h, g, used);
		}
	}
}

double solve(int n, int m, int k, int h, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
	vector<vector<pair<ll, ll>>> g(n);
	for (ll i = 0; i < m; i++) {
		g[x[i]].emplace_back(y[i], c[i]);
		g[y[i]].emplace_back(x[i], c[i]);
	}
	vector<bool> used(n, false);
	dfs(0, h, g, used);
	if (!used[h]) {
		return -1;
	}
	vector<double> dist(n, INF);
	dist[0] = 0;
	for (ll i = 0; i < n; i++) {
		if (arr[i] == 0 && used[i]) {
			dist[i] = 0;
		}
	}
	if (k > 70) {
		k = 70;
	}
	for (ll nd = 0; nd <= k; nd++) {
		set<pair<double, ll>> pq;
		for (ll i = 0; i < n; i++) {
			if (dist[i] != INF) {
				pq.insert(make_pair(dist[i], i));
			}
		}
		while (!pq.empty()) {
			auto[d, v] = *pq.begin();
			pq.erase(pq.begin());
			if (v == h) {
				continue;
			}
			for (auto[i, c] : g[v]) {
				if (c + d < dist[i]) {
					pq.erase(make_pair(dist[i], i));
					dist[i] = c + d;
					pq.insert(make_pair(dist[i], i));
				}
			}
		}
		if (nd == k) {
			continue;
		}
		vector<pair<ll, double>> upd;
		for (ll i = 0; i < n; i++) {
			if (arr[i] == 2 && dist[i] != INF) {
				dist[i] /= 2;
				for (auto[v, c] : g[i]) {
					upd.emplace_back(v, c + dist[i]);
				}
				dist[i] = INF;
			}
		}
		for (auto[v, d] : upd) {
			if (dist[v] > d) {
				dist[v] = d;
			}
		}
	}
	return dist[h];
}

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 13 / 13
• Subtask 4: 19 / 19
• Subtask 5: 7 / 7
• Subtask 6: 16 / 16
• Subtask 7: 29 / 29
• Subtask 8: 3 / 3