Submission #844993

#	Time	Username	Problem	Language	Result	Execution time	Memory
844993		gtm7	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	197 ms	20404 KiB

commuter_pass

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

const long long mx = 100000000000000000;
void dijkstra(int ss, vector<pair<int, int>> adj[], vector<int> &arr, vector<long long> &d)
{
    using T = pair<long long, int>;
    priority_queue<T, vector<T>, greater<T>> q;
    q.push({0, ss});
    d[ss] = 0;
    long long s, cd;
    while (!q.empty())
    {
        s = q.top().second;
        cd = q.top().first;
        q.pop();
        if (cd > d[s])
            continue;
        arr.push_back(s);
        for (auto x : adj[s])
        {
            if (d[x.first] > d[s] + x.second)
            {
                d[x.first] = d[s] + x.second;
                q.push({d[x.first], x.first});
            }
        }
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, m, ss, tt, u, v;
    cin >> n >> m >> ss >> tt >> u >> v;
    ss--, tt--, u--, v--;
    int a, b, c;
    vector<pair<int, int>> adj[n];
    for (int i = 0; i < m; i++)
    {
        cin >> a >> b >> c;
        adj[a - 1].push_back({b - 1, c});
        adj[b - 1].push_back({a - 1, c});
    }
    long long vd, ud;
    vector<long long> du(n, mx);
    vector<long long> dv(n, mx);
    vector<long long> dsum(n);
    vector<long long> d(n, mx);
    vector<int> brr;
    vector<int> arr;
    dijkstra(u, adj, brr, du);
    dijkstra(v, adj, brr, dv);
    dijkstra(ss, adj, arr, d);
    for (int i = 0; i < n; i++)
    {
        dsum[i] = du[i] + dv[i];
    }
    long long ans = dsum[v];
    for (auto i : arr)
    {
        vd = dv[i];
        ud = du[i];
        for (auto x : adj[i])
        {
            if (d[i] == d[x.first] + x.second)
            {
                du[i] = min(du[i], du[x.first]);
                dv[i] = min(dv[i], dv[x.first]);
            }
        }
        dsum[i] = min(du[i] + vd, dv[i] + ud);
        for (auto x : adj[i])
        {
            if (d[i] == d[x.first] + x.second)
            {
                dsum[i] = min(dsum[i], dsum[x.first]);
            }
        }
    }
    ans = min(ans, dsum[tt]);
    cout << ans << "\n";
    return 0;
}

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