Submission #1033522

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033522		Luvidi	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	214 ms	25508 KiB

commuter_pass

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

#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define fs first
#define sc second
#define pb push_back

const int maxn=1e5;
int n,m;
vector<pll> adj[maxn+1];
ll ds[maxn+1],dx[maxn+1],dy[maxn+1],dp1[maxn+1],dp2[maxn+1],ans=1e18;

void dj(int v,ll dist[]){
    for(int i=1;i<=n;i++)dist[i]=1e18;
    bool vis[n+1];
    memset(vis,0,sizeof(vis));
    priority_queue<pll> pq;
    dist[v]=0;
    pq.push({0,v});
    while(!pq.empty()){
        ll i=pq.top().sc;
        pq.pop();
        if(vis[i])continue;
        vis[i]=1;
        for(auto[u,w]:adj[i])if(!vis[u]){
            dist[u]=min(dist[u],dist[i]+w);
            pq.push({-dist[u],u});
        }
    }
}

ll f1(int v){
    if(dp1[v]!=-1)return dp1[v];
    ll x=dy[v];
    for(auto[u,w]:adj[v]){
        if(ds[v]==ds[u]+w){
            ll y=f1(u);
            x=min(x,y);
            ans=min(ans,dx[v]+y);
        }
    }
    return dp1[v]=x;
}

ll f2(int v){
    if(dp2[v]!=-1)return dp2[v];
    ll x=dx[v];
    for(auto[u,w]:adj[v]){
        if(ds[v]==ds[u]+w){
            ll y=f2(u);
            x=min(x,y);
            ans=min(ans,dy[v]+y);
        }
    }
    return dp2[v]=x;
}
void solve() {
    cin>>n>>m;
    int s,t,x,y;
    cin>>s>>t>>x>>y;
    while(m--){
        int u,v,w;
        cin>>u>>v>>w;
        adj[u].pb({v,w});
        adj[v].pb({u,w});
    }
    dj(s,ds);
    dj(x,dx);
    dj(y,dy);
    memset(dp1,-1,sizeof(dp1));
    f1(t);
    memset(dp2,-1,sizeof(dp2));
    f2(t);
    cout<<min(ans,dx[y]);
}

int main() {   
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    solve();
}

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