Submission #535716

#	Time	Username	Problem	Language	Result	Execution time	Memory
535716		sam571128	Olympic Bus (JOI20_ho_t4)	C++17	5 / 100	1095 ms	4272 KiB

ho_t4

#include <bits/stdc++.h>

#define int long long
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

using namespace std;

const int N = 205;

struct edge{
    int u,v,w,x;
};

vector<edge> edges;
vector<int> adj[N];
int dis[N];
int n,m;

int ans = 1e18;

void dijkstra(int tmp){
    int res = 0;
    fill(dis,dis+N,1e18);
    priority_queue<pair<int,int>,vector<pair<int,int>>,greater<>> pq;
    dis[1] = 0;
    pq.push({0,1});

    while(!pq.empty()){
        auto [ww,u] = pq.top(); pq.pop();
        if(ww > dis[u]) continue;
        for(auto eid : adj[u]){
            if(edges[eid].u==u){
                if(dis[edges[eid].v] > dis[u] + edges[eid].w){
                    dis[edges[eid].v] = dis[u] + edges[eid].w;
                    pq.push({dis[edges[eid].v],edges[eid].v});
                }
            }
        }
    }
    res += dis[n];

    fill(dis,dis+N,1e18);
    dis[n] = 0;
    pq.push({0,n});

    while(!pq.empty()){
        auto [ww,u] = pq.top(); pq.pop();
        if(ww > dis[u]) continue;
        for(auto eid : adj[u]){
            if(edges[eid].u==u){
                if(dis[edges[eid].v] > dis[u] + edges[eid].w){
                    dis[edges[eid].v] = dis[u] + edges[eid].w;
                    pq.push({dis[edges[eid].v],edges[eid].v});
                }
            }
        }
    }
    res += dis[1];
    ans = min(ans,res+tmp);
}

signed main(){
    fastio
    cin >> n >> m;

    for(int i = 0;i < m;i++){
        int u,v,c,d;
        cin >> u >> v >> c >> d;
        adj[u].push_back(edges.size());
        adj[v].push_back(edges.size());
        edges.push_back({u,v,c,d});
    }

    dijkstra(0);

    for(auto &e : edges){
        swap(e.u,e.v);
        dijkstra(e.x);
        swap(e.u,e.v);
    }

    cout << (ans==1e18 ? -1 : ans) << "\n";
}

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