Submission #545741

#	Time	Username	Problem	Language	Result	Execution time	Memory
545741		Jomnoi	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	360 ms	20176 KiB

commuter_pass

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

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

vector <pair <int, int>> adj[N];

int n;
long long ans;
long long dist[4][N], dist2[N];
bool visited[4][N], visited2[N];

void Dijkstra(int id, int s) {
    fill(dist[id], dist[id] + n + 1, INF);

    priority_queue <pair <long long, int>> pq;
    pq.emplace(0, s);
    dist[id][s] = 0;
    while(!pq.empty()) {
        int u = pq.top().second;
        pq.pop();

        if(visited[id][u] == true) {
            continue;
        }
        visited[id][u] = true;
        for(auto [v, w] : adj[u]) {
            if(visited[id][v] == false and dist[id][u] + w < dist[id][v]) {
                dist[id][v] = dist[id][u] + w;
                pq.emplace(-dist[id][v], v);
            }
        }
    }
}

void dfs(int id, int u) {
    dist2[u] = dist[3][u];
    visited2[u] = true;
    for(auto [v, w] : adj[u]) {
        if(dist[id ^ 1][v] + w == dist[id ^ 1][u]) {
            if(visited2[v] == false) {
                dfs(id, v);
            }
            dist2[u] = min(dist2[u], dist2[v]);
        }
    }
    ans = min(ans, dist2[u] + dist[2][u]);
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int m, S, T, U, V;
    cin >> n >> m >> S >> T >> U >> V;
    while(m--) {
        int a, b, c;
        cin >> a >> b >> c;
        adj[a].emplace_back(b, c);
        adj[b].emplace_back(a, c);
    }

    Dijkstra(0, S);
    Dijkstra(1, T);
    Dijkstra(2, U);
    Dijkstra(3, V);

    ans = dist[2][V];

    dfs(0, S);
    fill(visited2, visited2 + n + 1, false);
    dfs(1, T);

    cout << ans;
    return 0;
}

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