Submission #1009016

#	Time	Username	Problem	Language	Result	Execution time	Memory
1009016		christinelynn	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	916 ms	262144 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'
#define hitaf ios_base::sync_with_stdio(false); cin.tie(NULL);
#define fi first
#define se second

const ll MOD = 998244353;
const ll INF = 1e18;

ll n, m, s, t, u, V;
vector<pair<ll, ll>> adj[100005];
bool vis[100005];

int main(){
    //hitaf
    cin >> n >> m;
    cin >> s >> t;
    cin >> u >> V;
    
    vector<ll> dist(n + 2, INF), dist2(n + 2, INF);
    
    for(int i = 1; i <= m; i++){
        ll x, y, w;
        cin >> x >> y >> w;
        adj[x].push_back({y, w});
        adj[y].push_back({x,w});
    }
        
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> pq;
    pq.push({0, s});
    dist[s] = 0;    
    while(!pq.empty()){
        auto now = pq.top();
        pq.pop();
        
        if(dist[now.se] < now.fi) continue;
        for(auto v: adj[now.se]){
            if(dist[v.fi] < now.fi + v.se) continue;
            dist[v.fi] = now.fi + v.se;
            pq.push({dist[v.fi], v.fi});
        }
    }
        
    vector<ll> p(n + 2, -1);
    queue<ll> q;
    q.push(t);
    while(!q.empty()){
        ll now = q.front();
        q.pop();
        for(auto v: adj[now]){
            if(dist[v.fi] + v.se == dist[now]){
                p[now] = v.fi;
                if(vis[v.fi]) continue;
                vis[v.fi] = true;
                q.push(v.fi);
            }
        }
    }
    
    vector<bool> vis2(n + 2);
    priority_queue<pair<ll, pair<ll, ll>>, vector<pair<ll, pair<ll, ll>>>, greater<pair<ll, pair<ll, ll>>>> pq2;
    pq2.push({0, {u, -1}});
    while(!pq2.empty()){
        auto now = pq2.top();
        pq2.pop();
        
        if(dist2[now.se.fi] < now.fi || vis2[now.se.fi]) continue;
        vis2[now.se.fi] = true;
        for(auto v: adj[now.se.fi]){
            ll w = v.se;
            if((p[now.se.fi] == v.fi && (now.se.se == 0 || now.se.se == -1)) || (p[v.fi] == now.se.fi && (now.se.se == 1 || now.se.se == -1))) w = 0;
            //if(now.se.fi == 2) cout << w << " " << v.fi << endl; 
            if(dist2[v.fi] < now.fi + w) continue;
            
            dist2[v.fi] = now.fi + w;
            
            ll tmp = now.se.se;
            if(tmp == -1){
                if(p[now.se.fi] == v.fi) tmp = 0;
                else if(p[v.fi] == now.se.fi) tmp = 1;
            }
            pq2.push({dist2[v.fi], {v.fi, tmp}});
        }
    }
            
    //for(auto x: st) cout << x.fi << " " << x.se << endl;
    cout << dist2[V] << endl;        
}
    

/*
    7 1 2 9 0
*/

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