Submission #1318552

#	Time	Username	Problem	Language	Result	Execution time	Memory
1318552		peanut	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	171 ms	16084 KiB

commuter_pass

#include <bits/stdc++.h>

using namespace std;
const int maxn = 1e5 + 5;

int n, m;
int S, T, U, V;
vector<pair<int, int>> adj[maxn];
vector<long long> dijkstra(int so) {
    vector<long long> dist(n+1, LLONG_MAX);
    dist[so] = 0;
    priority_queue<pair<long long, int>> pq;
    pq.push({0, so});
    while (!pq.empty()) {
        long long d = -pq.top().first;
        int y = pq.top().second;
        pq.pop();
        if (d != dist[y]) continue;
        for (auto x : adj[y]) {
            if (d + x.second < dist[x.first]) {
                dist[x.first] = d + x.second;
                pq.push({-dist[x.first], x.first});
            }
        }
    }
    return dist;
}
int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    //freopen("PATH.INP", "r", stdin);
    //freopen("PATH.OUT", "w", stdout);
    cin >> n >> m >> S >> T >> U >> V;
    for (int i = 1; i <= m; ++i) {
        int u, v, w; cin >> u >> v >> w;
        adj[u].push_back({v, w});
        adj[v].push_back({u, w});
    }

    vector<long long> distU = dijkstra(U);
    vector<long long> distV = dijkstra(V);
    vector<long long> dist(n+1, LLONG_MAX), mindistU(n+1, LLONG_MAX), mindistV(n+1, LLONG_MAX);
    dist[S] = 0, mindistU[S] = distU[S], mindistV[S] = distV[S];
    priority_queue<pair<long long, int>> pq;
    pq.push({0, S});
    while (!pq.empty()) {
        long long d = -pq.top().first;
        int y = pq.top().second;
        pq.pop();
        if (d != dist[y]) continue;
        for (auto x : adj[y]) {
            if (d + x.second < dist[x.first]) {
                dist[x.first] = d + x.second;
                mindistU[x.first] = min(mindistU[y], distU[x.first]);
                mindistV[x.first] = min(mindistV[y], distV[x.first]);
                pq.push({-dist[x.first], x.first});
            }
            else if (d + x.second == dist[x.first]) {
                if (min(mindistU[y], distU[x.first]) + min(mindistV[y], distV[x.first]) < mindistU[x.first] + mindistV[x.first]) {
                    mindistU[x.first] = min(mindistU[y], distU[x.first]);
                    mindistV[x.first] = min(mindistV[y], distV[x.first]);
                }
            }
        }
    }
    cout << min(distU[V], mindistU[T] + mindistV[T]);
    return 0;
}

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