제출 #519334

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
519334		Netr	Commuter Pass (JOI18_commuter_pass)	C++11	31 / 100	483 ms	35776 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pi;

const ll MAXN = 1e5 + 5;
const ll INF = 1ll<<62;

ll N,M,S,T,U,V,D[MAXN],vis[MAXN];

vector<pi> edge[MAXN];
vector<ll> succ[MAXN], pred[MAXN];

void dfs(int i){
    vis[i] = 1;
    if(i == S) return;
    for(auto e : edge[i]){
        if(D[e.first] + e.second == D[i]){
            succ[e.first].push_back(i);
            pred[i].push_back(e.first);
            if(!vis[e.first]) dfs(e.first);
        }
    }
}

int main(){
    cin >> N >> M >> S >> T >> U >> V;
    for(int i = 0; i < M; i++){
        ll ai, bi, ci;
        cin >> ai >> bi >> ci;
        edge[bi].push_back({ai, ci});
        edge[ai].push_back({bi, ci});
    }
    
    priority_queue<pi, vector<pi>, greater<pi>> pq;
    fill(begin(D), end(D), INF);
    D[S] = 0;
    pq.push({0, S});
    while(!pq.empty()){
        pi t = pq.top(); pq.pop();
        if(t.first != D[t.second]) continue;
        if(t.second == T) break;
        for(auto e : edge[t.second]){
            if(D[t.second] + e.second < D[e.first]){
                pq.push({D[e.first] = D[t.second] + e.second, e.first});
            }
        }
    }
    dfs(T);

    pq = priority_queue<pi, vector<pi>, greater<pi>>();
    fill(begin(D), end(D), INF);
    fill(begin(vis), end(vis), 0);
    vis[U] = 1;
    D[U] = 0;
    pq.push({0, U});
    while(!pq.empty()){
        pi t = pq.top(); pq.pop();
        if(t.first != D[t.second]) continue;
        if(t.second == V) break;
        vis[t.second] = 1;
        for(int e : succ[t.second]){
            if(!vis[e]){
                vis[e] = 1;
                pq.push({D[e] = D[t.second], e});
            }
        }
        for(auto e : edge[t.second]){
            if(D[t.second] + e.second < D[e.first] && !vis[e.first]){
                pq.push({D[e.first] = D[t.second] + e.second, e.first});
            }
        }
    }
    ll ans = D[V];

    //now do it again with pred
    pq = priority_queue<pi, vector<pi>, greater<pi>>();
    fill(begin(D), end(D), INF);
    fill(begin(vis), end(vis), 0);
    vis[U] = 1;
    D[U] = 0;
    pq.push({0, U});
    while(!pq.empty()){
        pi t = pq.top(); pq.pop();
        if(t.first != D[t.second]) continue;
        if(t.second == V) break;
        vis[t.second] = 1;
        for(int e : pred[t.second]){
            if(!vis[e]){
                vis[e] = 1;
                pq.push({D[e] = D[t.second], e});
            }
        }
        for(auto e : edge[t.second]){
            if(D[t.second] + e.second < D[e.first] && !vis[e.first]){
                pq.push({D[e.first] = D[t.second] + e.second, e.first});
            }
        }
    }
    cout << min(ans, D[V]) << "\n";
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45