Submission #1130208

#	Time	Username	Problem	Language	Result	Execution time	Memory
1130208		enzy	Commuter Pass (JOI18_commuter_pass)	C++20	15 / 100	588 ms	24892 KiB

commuter_pass

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int maxn=1e5+10;
const int inf=1e15+10;
vector<pair<int,int>>adj[maxn];
vector<int>vim[maxn];
int dist[maxn][3], n, marc[maxn]; 
//dist[i][?] 0-> dist a partir do u, 1-> dist a partir do v, 2-> dist a partir do s
void dijkstra(int x, int t){
    for(int i=1;i<=n;i++) dist[i][t]=inf;
    dist[x][t]=0;
    set<pair<int,int>>s;
    for(int i=1;i<=n;i++) s.insert({dist[i][t],i});
    while(!s.empty()){
        auto f=s.begin();
        int u=f->second;
        s.erase(f);
        for(auto p : adj[u]){
            int viz=p.first, w=p.second;
            if(dist[u][t]+w<dist[viz][t]){
                s.erase({dist[viz][t],viz});
                dist[viz][t]=dist[u][t]+w;
                s.insert({dist[viz][t],viz});
                vim[viz].clear();
            }
            if(dist[u][t]+w==dist[viz][t]&&t==2) vim[viz].push_back(u);
        }
    }
}
signed main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    int m, s, t, u, v; cin >> n >> m >> s >> t >> u >> v;
    for(int i=1;i<=m;i++){
        int a, b, c; cin >> a >> b >> c;
        adj[a].push_back({b,c});
        adj[b].push_back({a,c});
    }
    dijkstra(u,0);
    int resp=dist[v][0];
    dijkstra(v,1);
    dijkstra(s,2);
    queue<int>q;
    vim[s].clear();
    marc[t]++;
    for(auto a : vim[t]) q.push(a);
    while(!q.empty()){
        int at=q.front(); q.pop();
        marc[at]++;
        for(auto a : vim[at]){
            if(marc[a]) continue;
            q.push(a);
        }
        if(at==s) break;
    }
    int du=inf, dv=inf;
    for(int i=1;i<=n;i++){
        if(marc[i]){
            du=min(du,dist[i][0]);
            dv=min(dv,dist[i][1]);
        }
    }
    if(marc[u]) du=0;
    if(marc[v]) dv=0;
    resp=min(resp,dv+du);
    cout << resp << endl;
    return 0;
}
//

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