Submission #544911

#	Time	Username	Problem	Language	Result	Execution time	Memory
544911		pokmui9909	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	389 ms	23200 KiB

commuter_pass

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

#define x first
#define y second
ll N, M, S, T, U, V;
vector<pair<ll, ll>>  G[100005];
ll dpU[100005], dpV[100005];
vector<ll> insp;
vector<ll> dS, dT, dU, dV;
const ll INF = 1e18;
vector<ll> dijkstra(ll s){
    vector<ll> d(N, INF);
    priority_queue<pair<ll, ll>> PQ;
    d[s] = 0; PQ.push({0, s});
    while(!PQ.empty()){
        ll c = -PQ.top().x, u = PQ.top().y; PQ.pop();
        for(auto i : G[u]){
            ll v = i.x, nc = c + i.y;
            if(d[v] <= nc) continue;
            d[v] = nc;
            PQ.push({-nc, v});
        }
    }
    return d;
}

int main(){
    cin.tie(0) -> sync_with_stdio(false);

    cin >> N >> M >> S >> T >> U >> V;
    S--, T--, U--, V--;
    for(int i = 0; i < M; i++){
        ll u, v, c; cin >> u >> v >> c;
        u--, v--;
        G[u].push_back({v, c});
        G[v].push_back({u, c});
    }
    dS = dijkstra(S), dT = dijkstra(T), dU = dijkstra(U), dV = dijkstra(V);
    for(int i = 0; i < N; i++){
        if(dS[i] + dT[i] == dS[T]){
            insp.push_back(i);
        }
    }
    sort(insp.begin(), insp.end(), [&](ll a, ll b) -> bool{return dS[a] < dS[b];});
    fill(dpU, dpU + N, INF);
    for(auto u : insp) dpU[u] = dU[u];
    for(auto u : insp){
        for(auto i : G[u]){
            ll v = i.x;
            if(dS[v] + dT[v] != dS[T] || dS[u] > dS[v]) continue;
            dpU[v] = min(dpU[v], dpU[u]);
        }
    }
    fill(dpV, dpV + N, INF);
    for(auto u : insp) dpV[u] = dV[u];
    for(auto u : insp){
        for(auto i : G[u]){
            ll v = i.x;
            if(dS[v] + dT[v] != dS[T] || dS[u] > dS[v]) continue;
            dpV[v] = min(dpV[v], dpV[u]);
        }
    }
    ll ans = dU[V];
    for(auto i : insp){
        ans = min({ans, dpU[i] + dV[i], dpV[i] + dU[i]});
    }
    cout << ans;
}

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