Submission #1146712

#	Time	Username	Problem	Language	Result	Execution time	Memory
1146712		koukirocks	Olympic Bus (JOI20_ho_t4)	C++20	5 / 100	1094 ms	2632 KiB

ho_t4

#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second

using namespace std;
typedef pair<int,int> pii;
typedef long long ll;
typedef pair<ll,ll> pll;
const int INF=0x3f3f3f3f;
const ll oo=0x3f3f3f3f3f3f3f3f;
template<class T>
using vvector = vector<vector<T>>;

struct edge {
    ll a,b,c,d;
};

ll dijkstra(int st,int ed,vvector<pii> &G,vector<edge> &E,int rid,int n) {
    vector<ll> dis(n+1,oo);
    vector<bool> vis(n+1);
    priority_queue<pll> pq;
    dis[st]=0;
    pq.emplace(0,st);
    while (!pq.empty()) {
        while (!pq.empty() and vis[pq.top().S]) pq.pop();
        if (pq.empty()) break;
        auto [d,v]=pq.top();
        pq.pop();
        vis[v]=true;
        for (auto [i,id]:G[v]) {
            if (id==rid) continue;
            if (vis[i]) continue;
            if (dis[i]>dis[v]+E[id].c) {
                dis[i]=dis[v]+E[id].c;
                pq.emplace(-dis[i],i);
            }
        }
        if (E[rid].b==v) {
            int i=E[rid].a;
            int id=rid;
            if (vis[i]) continue;
            if (dis[i]>dis[v]+E[id].c) {
                dis[i]=dis[v]+E[id].c;
                pq.emplace(-dis[i],i);
            }
        }
    }
    return dis[ed];
}

int main() {
    speed;
    int n,m;
    cin>>n>>m;
    vector<edge> E(m+1);
    vvector<pii> G(n+1);
    for (int i=1;i<=m;i++) {
        ll a,b,c,d;
        cin>>a>>b>>c>>d;
        G[a].emplace_back(b,i);
        E[i]={a,b,c,d};
    }
    ll ans=oo;
    for (int i=0;i<=m;i++) {
        ll now=E[i].d+dijkstra(1,n,G,E,i,n)+dijkstra(n,1,G,E,i,n);
        ans=min(ans,now);
    }
    cout<<(ans==oo?-1:ans)<<"\n";
    return 0;
}

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