Submission #714540

#	Time	Username	Problem	Language	Result	Execution time	Memory
714540		tcmmichaelb139	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	1132 ms	262144 KiB

commuter_pass

#include "bits/stdc++.h"
using namespace std;

struct node {
    int v;
    long long dist, mtu, mtv;

    bool operator<(const node &rhs) const {
        return dist > rhs.dist;
    }
};

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int N, M, S, T, U, V;
    cin >> N >> M >> S >> T >> U >> V;
    vector<pair<int, long long>> adj[N + 1];
    for (int i = 0; i < M; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        adj[a].push_back({b, c});
        adj[b].push_back({a, c});
    }

    auto distcalc = [&](int s) {
        priority_queue<pair<long long, int>, vector<pair<long long, int>>, greater<pair<long long, int>>> q;
        vector<long long> dist(N + 1, 1e18);
        vector<bool> vis(N + 1);

        q.push({0, s});
        while (!q.empty()) {
            pair<long long, int> v = q.top();
            q.pop();

            if (vis[v.second]) continue;
            vis[v.second] = true;

            dist[v.second] = v.first;

            for (auto u : adj[v.second]) {
                q.push({u.second + v.first, u.first});
            }
        }

        return dist;
    };

    vector<long long> fu = distcalc(U), fv = distcalc(V);

    priority_queue<node> q;
    vector<long long> dist(N + 1, 1e18);

    q.push({S, 0, min((long long)1e18, fu[S]), min((long long)1e18, fv[S])});

    long long bt = -1, ans = 1e18;

    while (!q.empty()) {
        node v = q.top();
        q.pop();

        if (v.v == T) {
            if (bt == -1)
                bt = v.dist;
            if (bt == v.dist)
                ans = min(ans, v.mtu + v.mtv);
        }

        if (dist[v.v] < v.dist) continue;
        dist[v.v] = v.dist;

        for (auto u : adj[v.v]) {
            q.push({u.first, v.dist + u.second, min(v.mtu, fu[u.first]), min(v.mtv, fv[u.first])});
        }
    }
    cout << min(ans, fu[V]) << '\n';
}

• Subtask 1: 0 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45