Submission #424988

#TimeUsernameProblemLanguageResultExecution timeMemory
424988nkatoCommuter Pass (JOI18_commuter_pass)C++17
100 / 100
724 ms31512 KiB
#include <bits/stdc++.h>

typedef long long ll;

using namespace std;


vector<pair<ll, ll>> graph[100001];

ll du[100001], dv[100001], ds[100001], dp[2][100001], ans;

bool visited[100001];


void dijkstra1(ll start, ll arr[]) {

    fill(visited, visited + 100001, false);


    priority_queue<pair<ll, ll>> pq;

    pq.push({0, start});

    while (!pq.empty()) {

        ll c, node;

        tie(c, node) = pq.top();

        pq.pop();


        if (!visited[node]) {

            arr[node] = -c;

            visited[node] = true;

            for (auto& i : graph[node]) pq.push({c - i.second, i.first});

        }

    }

}


void dijkstra2(ll start, ll end) {

    fill(dp[0], dp[0] + 100001, LLONG_MAX / 2);

    fill(dp[1], dp[1] + 100001, LLONG_MAX / 2);

    fill(visited, visited + 100001, false);


    priority_queue<pair<ll, pair<ll, ll>>> pq;

    pq.push({0, {start, 0}});

    dp[0][0] = dp[1][0] = LLONG_MAX/ 2;

    while (!pq.empty()) {

        ll c, node, par;

        pair<ll, ll> p;

        tie(c, p) = pq.top();

        tie(node, par) = p;

        pq.pop();


        if (!visited[node]) {

            visited[node] = true;

            ds[node] = -c;

            dp[0][node] = min(du[node], dp[0][par]);

            dp[1][node] = min(dv[node], dp[1][par]);

            for (auto i : graph[node]) pq.push({c - i.second, {i.first, node}});

        } else if (-c == ds[node]) {

            if (min(du[node], dp[0][par]) + min(dv[node], dp[1][par]) <= dp[0][node] + dp[1][node]) {

                dp[0][node] = min(du[node], dp[0][par]);

                dp[1][node] = min(dv[node], dp[1][par]);

            }

        }

    }


    ans = min(ans, dp[0][end] + dp[1][end]);

}


int main() {

    iostream::sync_with_stdio(false);

    cin.tie(0);

    ll n, m, s, t, u, v;

    cin >> n >> m >> s >> t >> u >> v;

    for (int i = 0; i < m; i++) {

        ll a, b, c;

        cin >> a >> b >> c;

        graph[a].push_back({b, c});

        graph[b].push_back({a, c});

    }


    dijkstra1(u, du);

    dijkstra1(v, dv);


    ans = du[v];


    dijkstra2(s, t);

    dijkstra2(t, s);


    cout << ans << '\n';

    return 0;

}
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