Submission #1016277

#	Time	Username	Problem	Language	Result	Execution time	Memory
1016277		Aiperiii	Olympic Bus (JOI20_ho_t4)	C++14	26 / 100	1039 ms	4460 KiB

ho_t4

#include <bits/stdc++.h>
//#define int long long
#define all(x) x.begin(),x.end()
#define ff first
#define ss second
#define pb push_back
using namespace std;
const int N=5e4+5;
vector <pair <pair <int,int> ,int> > g[2][205];
int p[4][205],dis[4][205];
int a[N],b[N],c[N],d[N],used[N];

priority_queue <pair <int,int> > pq;

void djkstra(int n,int tp,int x){
    dis[x][n]=0;
    pq.push({0,n});
    while(!pq.empty()){
        int v=pq.top().ss;
        pq.pop();
        for(auto to : g[tp][v]){
            if(dis[x][to.ff.ff]>dis[x][v]+to.ff.ss){
                dis[x][to.ff.ff]=dis[x][v]+to.ff.ss;
                p[x][to.ff.ff]=to.ss;
                pq.push({dis[x][to.ff.ff],to.ff.ff});
            }
        }
    }
}

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        cin>>a[i]>>b[i]>>c[i]>>d[i];
        g[0][a[i]].pb({{b[i],c[i]},i});
        g[1][b[i]].pb({{a[i],c[i]},i});
    }
    
    for(int i=1;i<=n;i++){
        for(int j=0;j<4;j++){
            dis[j][i]=1e9;
        }
    }
    djkstra(1,0,0);
    djkstra(1,1,1);
    djkstra(n,0,2);
    djkstra(n,1,3);
    /*for(int x=0;x<4;x++){
        for(int i=1;i<=n;i++){
            cout<<dis[x][i]<<" ";
        }
        cout<<"\n";
    }
    cout<<"\n";*/
    for(int x=0;x<4;x++){
        for(int i=1;i<=n;i++){
            used[p[x][i]]=1;
        }
    }
    int mn=2e9;
    if(dis[0][n]<1e9 && dis[2][1]<1e9)mn=min(dis[0][n]+dis[2][1],mn);
    
    for(int i=1;i<=m;i++){
        if(!used[i]){
            int new1n=min(dis[0][n],dis[0][b[i]]+dis[3][a[i]]+c[i]);
            int newn1=min(dis[2][1],dis[2][b[i]]+dis[1][a[i]]+c[i]);
            if(new1n<1e9 && newn1<1e9)mn=min(mn,new1n+newn1+d[i]);
        }
        else{
            vector <int> dist(n+1,1e9);
            dist[1]=0;
            pq.push({0,1});
            while(!pq.empty()){
                int v=pq.top().ss;
                pq.pop();
                if(v==b[i]){
                    if(dist[a[i]]>dist[b[i]]+c[i]){
                        dist[a[i]]=dist[b[i]]+c[i];
                        pq.push({dist[a[i]],a[i]});
                    }
                }
                for(auto to : g[0][v]){
                    if(to.ss==i)continue;
                    if(dist[to.ff.ff]>dist[v]+to.ff.ss){
                        dist[to.ff.ff]=dist[v]+to.ff.ss;
                        pq.push({dist[to.ff.ff],to.ff.ff});
                    }
                }
            }
            if(dist[n]<1e9){
                int ans=dist[n];
                for(int j=1;j<=n;j++){
                    dist[j]=1e9;
                }
                dist[n]=0;
                pq.push({0,n});
                while(!pq.empty()){
                    int v=pq.top().ss;
                    pq.pop();
                    if(v==b[i]){
                        if(dist[a[i]]>dist[b[i]]+c[i]){
                            dist[a[i]]=dist[b[i]]+c[i];
                            pq.push({dist[a[i]],a[i]});
                        }
                    }
                    for(auto to : g[0][v]){
                        if(to.ss==i)continue;
                        if(dist[to.ff.ff]>dist[v]+to.ff.ss){
                            dist[to.ff.ff]=dist[v]+to.ff.ss;
                            pq.push({dist[to.ff.ff],to.ff.ff});
                        }
                    }
                }
                if(dist[1]<1e9)mn=min(mn,ans+dist[1]+d[i]);
                
            }
        }
    }
    if(mn==2e9)mn=-1;
    cout<<mn<<"\n";
    
}
//g[1]-r
//dis[0] 1
//dis[1] 1r
//dis[2] n
//dis[3] nr

/*

*/

• Subtask 1: 5 / 5
• Subtask 2: 0 / 11
• Subtask 3: 21 / 21
• Subtask 4: 0 / 63