Submission #547294

#	Time	Username	Problem	Language	Result	Execution time	Memory
547294		Jomnoi	Cities (BOI16_cities)	C++17	100 / 100	1784 ms	44784 KiB

cities

#include <bits/stdc++.h>
#define DEBUG 0
using namespace std;

const int MAX_N = 1e5 + 10;
const long long INF = 1e18 + 7;

int n;
vector <pair <int, int>> graph[MAX_N];
long long dist[32][MAX_N];

void Dijkstra(int mask) {
    priority_queue <pair <long long, int>> pq;
    for(int i = 1; i <= n; i++) {
        if(dist[mask][i] != INF) {
            pq.emplace(-dist[mask][i], i);
        }
    }
    while(!pq.empty()) {
        auto [d, u] = pq.top();
        pq.pop();

        if(dist[mask][u] < -d) {
            continue;
        }
        for(auto [v, w] : graph[u]) {
            if(dist[mask][u] + w < dist[mask][v]) {
                dist[mask][v] = dist[mask][u] + w;
                pq.emplace(-dist[mask][v], v);
            }
        }
    }
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int k, m;
    cin >> n >> k >> m;
    for(int i = 0; i < (1<<k); i++) {
        fill(dist[i], dist[i] + n + 1, INF);
    }
    for(int i = 0; i < k; i++) {
        int x;
        cin >> x;
        dist[1<<i][x] = 0;
    }
    while(m--) {
        int a, b, c;
        cin >> a >> b >> c;
        graph[a].emplace_back(b, c);
        graph[b].emplace_back(a, c);
    }

    for(int mask = 1; mask < (1<<k); mask++) {
        if(__builtin_popcount(mask) > 1) {
            for(int s = mask; s > 0; s = (s - 1) & mask) {
                for(int i = 1; i <= n; i++) {
                    dist[mask][i] = min(dist[mask][i], dist[s][i] + dist[mask ^ s][i]);
                }
            }
        }
        Dijkstra(mask);
    }

    long long ans = INF;
    for(int i = 1; i <= n; i++) {
        ans = min(ans, dist[(1<<k) - 1][i]);
    }
    cout << ans;
    return 0;
}

• Subtask 1: 22 / 22
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 26 / 26