Submission #983206

#	Time	Username	Problem	Language	Result	Execution time	Memory
983206		vjudge1	Cyberland (APIO23_cyberland)	C++17	0 / 100	1909 ms	2097152 KiB

cyberland

#include <vector>
#include <queue>
#include <climits>

using namespace std;

typedef pair<int, int> pii;

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

    // Priority queue to store (time, country) pairs, sorted by time.
    priority_queue<pii, vector<pii>, greater<pii>> pq;
    vector<vector<double>> dist(N, vector<double>(K + 1, INT_MAX));
    dist[0][0] = 0; // Distance to country 0 is 0, and no divide-by-2 ability used.

    // Push initial state into the priority queue.
    pq.push({0, 0});

    while (!pq.empty()) {
        int time = pq.top().first;
        int country = pq.top().second;
        pq.pop();

        if (country == H) // Reached Cyberland
            return time;

        // Check if using divide-by-2 ability is allowed at this country
        for (int k = 0; k <= K; ++k) {
            int next_time = (k < K) ? time / 2 : time; // If allowed, divide time by 2
            if (next_time < dist[country][k]) {
                dist[country][k] = next_time;
                pq.push({next_time, country});
            }
        }

        // Explore neighbors
        for (auto& neighbor : graph[country]) {
            int next_country = neighbor.first;
            int next_time = time + neighbor.second;

            // Check if special ability of the country exists
            if (arr[next_country] == 0)
                next_time = 0; // Special ability makes passing time 0
            else if (arr[next_country] == 2)
                next_time /= 2; // Special ability divides passing time by 2

            // Relaxation
            if (next_time < dist[next_country][0]) {
                dist[next_country][0] = next_time;
                pq.push({next_time, next_country});
            }
        }
    }

    return -1; // Cyberland is not reachable
}

• 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