Submission #963538

#	Time	Username	Problem	Language	Result	Execution time	Memory
963538		IBory	Cyberland (APIO23_cyberland)	C++17	0 / 100	528 ms	10716 KiB

cyberland

#include "cyberland.h"
#include <bits/stdc++.h>
#define pii pair<ll, ll>
typedef long long ll;
using namespace std;

const int MAX = 100007;
vector<pii> G[MAX];
bool V[MAX];
ll D[MAX], LD[MAX];

double solve(int N, int M, int K, int H, std::vector<int> x, std::vector<int> y, std::vector<int> c, std::vector<int> arr) {
	for (int i = 0; i < M; ++i) {
		G[x[i]].emplace_back(y[i], c[i]);
		G[y[i]].emplace_back(x[i], c[i]);
	}

	V[0] = 1;
	queue<int> Q;
	Q.push(0);
	while (!Q.empty()) {
		int cur = Q.front(); Q.pop();
		for (auto [next, _] : G[cur]) {
			if (V[next]) continue;
			V[next] = 1;
			Q.push(next);
		}
	}

	if (!V[H]) return -1;

	memset(D, 0x3f, sizeof(D));
	priority_queue<pii, vector<pii>, greater<pii>> PQ;
	for (int i = 0; i < N; ++i) {
		if (i && arr[i]) continue;
		PQ.emplace(D[i] = 0, i);
	}

	while (!PQ.empty()) {
		auto [cd, cur] = PQ.top(); PQ.pop();
		if (cd > D[cur]) continue;
		for (auto [next, nd] : G[cur]) {
			if (D[next] <= cd + nd) continue;
			PQ.emplace(D[next] = cd + nd, next);
		}
	}

	memset(LD, 0x3f, sizeof(LD));
	PQ.emplace(LD[H] = 0, H);
	while (!PQ.empty()) {
		auto [cd, cur] = PQ.top(); PQ.pop();
		if (cd > LD[cur]) continue;
		for (auto [next, nd] : G[cur]) {
			if (LD[next] <= cd + nd) continue;
			PQ.emplace(LD[next] = cd + nd, next);
		}
	}

	double ans = D[H];
	if (K) {
		for (int i = 1; i <= N; ++i) {
			if (arr[i] != 2 || !V[i]) continue;
			ll a = D[i], b = LD[i], c = 1e18;
			for (auto [next, nd] : G[i]) c = min(c, nd);

			double cd = (double)a / 2.0;
			for (int k = 1; k < min(100, K); ++k) {
				cd = (cd + 2LL * c) / 2.0;
			}

			ans = min(ans, cd);
		}
	}

	return ans;
}

Compilation message (stderr)

cyberland.cpp: In function 'double solve(int, int, int, int, std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
cyberland.cpp:63:17: warning: unused variable 'b' [-Wunused-variable]
   63 |    ll a = D[i], b = LD[i], c = 1e18;
      |                 ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 19
• Subtask 5: 0 / 7
• Subtask 6: 0 / 16
• Subtask 7: 0 / 29
• Subtask 8: 0 / 3