Submission #1032599

#	Time	Username	Problem	Language	Result	Execution time	Memory
1032599		MinhBoss	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	203 ms	30616 KiB

commuter_pass

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

#define ll long long
#define fi first
#define se second
#define pb push_back
#define endl '\n'
#define int long long

const ll MOD = 1e9+7;
void add(ll &x, const ll y){
    x+= y;
    if(x>=MOD) x-= MOD;
}
bool maximize(ll &x, const ll y){
    if(x < y){
        x = y; return true;
    }
    return false;
}
bool minimize(ll &x, const ll y){
    if(x > y){
        x = y; return true;
    }
    return false;
}

const ll MAX = 2e5+10, INF = 1e18;

ll n,m,k;
ll du[MAX], dv[MAX], ds[MAX], dpU[MAX], dpV[MAX];
bool vis[MAX];
vector<pair<ll,ll>>adj[MAX];
ll res=INF;

void dijkstra1(ll sta, ll *dist){
    priority_queue<pair<ll,ll>>q;

    dist[sta] = 0;
    q.push({0, sta});
    memset(vis, false, sizeof vis);
    while(!q.empty()){
        ll u = q.top().se;
        q.pop();
        if(vis[u]) continue;
        vis[u] =  true;
        for(auto p : adj[u]){
            if(dist[p.fi] > dist[u] + p.se){
                dist[p.fi] = dist[u] + p.se;
                q.push({-dist[p.fi], p.fi});
            }
        }
    }

}

void dijkstra2(ll sta, ll fin){
    memset(vis, false, sizeof vis);
    memset(dpU, 0x3f, sizeof dpU);
    memset(dpV, 0x3f, sizeof dpV);
    memset(ds, 0x3f, sizeof ds);

    priority_queue<pair<ll,ll>>q;
    ds[sta] = 0;
    dpU[sta] = du[sta];
    dpV[sta] = dv[sta];
    q.push({0,sta});

    while(!q.empty()){
        ll u= q.top().se;
        q.pop();
        if(vis[u]) continue;
        vis[u] = true;

        for(auto p : adj[u]){
            if(ds[p.fi] > ds[u] + p.se){
                ds[p.fi] = ds[u] + p.se;
                dpU[p.fi] = min(dpU[u], du[p.fi]);
                dpV[p.fi] = min(dpV[u], dv[p.fi]);
                q.push({-ds[p.fi], p.fi});
            }
            else if(ds[p.fi] == ds[u] + p.se && dpU[p.fi] + dpV[p.fi] > min(dpU[u], du[p.fi]) + min(dpV[u], dv[p.fi])){
                dpU[p.fi] = min(dpU[u], du[p.fi]);
                dpV[p.fi] = min(dpV[u], dv[p.fi]);
            }
        }
    }
    minimize(res, dpU[fin] + dpV[fin]);

}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

//    freopen("shortcut.in","r",stdin);
//    freopen("shortcut.out","w",stdout);
    int s,t,u,v;
    cin>>n>>m>>s>>t>>u>>v;

    for(int i =1;i<=m;i++){
        int u,v,w; cin>>u>>v>>w;
        adj[u].pb({v,w});
        adj[v].pb({u,w});
    }
    memset(du,0x3f, sizeof du);
    memset(dv, 0x3f, sizeof dv);
    dijkstra1(u,du);
    dijkstra1(v,dv);

    res = du[v];

    dijkstra2(s,t);
//    for(int i=1;i<=n;i++) cout<<ds[i]<<" ";
//    cout<<endl;
    cout<<res;
}

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