Submission #1016283

#	Time	Username	Problem	Language	Result	Execution time	Memory
1016283		Aiperiii	Olympic Bus (JOI20_ho_t4)	C++14	100 / 100	784 ms	5724 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[205];
int dist[205][205];
int a[N],b[N],c[N],d[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<=n;i++){
        for(int j=1;j<=n;j++){
            dist[i][j]=2e9;
        }
        dist[i][i]=0;
    }
    for(int i=1;i<=m;i++){
        cin>>a[i]>>b[i]>>c[i]>>d[i];
        dist[a[i]][b[i]]=min(dist[a[i]][b[i]],c[i]);
        g[a[i]].pb({{b[i],c[i]},i});
        
    }
    for(int k=1;k<=n;k++){
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++){
                dist[i][j]=min(dist[i][j],dist[i][k]+dist[k][j]);
            }
        }
    }
    
    int mn=2e9;
    mn=min(dist[1][n]+dist[n][1],mn);
    
    for(int i=1;i<=m;i++){
        int new1n=min(dist[1][n],dist[1][b[i]]+dist[a[i]][n]+c[i]);
        int newn1=min(dist[n][1],dist[n][b[i]]+dist[a[i]][1]+c[i]);
        if(new1n+newn1+d[i]>=mn)continue;
        
        vector <int> dis(n+1,2e9);
        dis[1]=0;
        pq.push({0,1});
        while(!pq.empty()){
            int v=pq.top().ss;
            pq.pop();
            if(v==b[i]){
                if(dis[a[i]]>dis[b[i]]+c[i]){
                    dis[a[i]]=dis[b[i]]+c[i];
                    pq.push({dis[a[i]],a[i]});
                }
            }
            for(auto to : g[v]){
                if(to.ss==i)continue;
                if(dis[to.ff.ff]>dis[v]+to.ff.ss){
                    dis[to.ff.ff]=dis[v]+to.ff.ss;
                    pq.push({dis[to.ff.ff],to.ff.ff});
                }
            }
        }
        if(dis[n]!=2e9){
            int ans=dis[n];
            for(int j=1;j<=n;j++){
                dis[j]=2e9;
            }
            dis[n]=0;
            pq.push({0,n});
            while(!pq.empty()){
                int v=pq.top().ss;
                pq.pop();
                if(v==b[i]){
                    if(dis[a[i]]>dis[b[i]]+c[i]){
                        dis[a[i]]=dis[b[i]]+c[i];
                        pq.push({dis[a[i]],a[i]});
                    }
                }
                for(auto to : g[v]){
                    if(to.ss==i)continue;
                    if(dis[to.ff.ff]>dis[v]+to.ff.ss){
                        dis[to.ff.ff]=dis[v]+to.ff.ss;
                        pq.push({dis[to.ff.ff],to.ff.ff});
                    }
                }
            }
            mn=min(mn,ans+dis[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: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 63 / 63