Submission #1331984

#TimeUsernameProblemLanguageResultExecution timeMemory
1331984ttamxCommuter Pass (JOI18_commuter_pass)C++20
100 / 100
151 ms16356 KiB
#include<bits/stdc++.h>

using namespace std;

using ll = long long;

const int N=1e5+5;
const int M=2e5+5;
const ll INF=1e18;

int n,m;
int s1,t1,s2,t2;
vector<pair<int,int>> adj[N];
ll distu[N],distv[N],dists[N];
ll dp[N][2][2];

void dijkstra(int st,ll *dist){
    for(int i=1;i<=n;i++)dist[i]=INF;
    dist[st]=0;
    using P = pair<ll,int>;
    priority_queue<P,vector<P>,greater<P>> pq;
    pq.emplace(0,st);
    while(!pq.empty()){
        auto [d,u]=pq.top();
        pq.pop();
        if(d>dist[u])continue;
        for(auto [v,w]:adj[u]){
            if(d+w<dist[v]){
                dist[v]=d+w;
                pq.emplace(dist[v],v);
            }
        }
    }
}

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n >> m >> s1 >> t1 >> s2 >> t2;
    for(int i=0;i<m;i++){
        int u,v,w;
        cin >> u >> v >> w;
        adj[u].emplace_back(v,w);
        adj[v].emplace_back(u,w);
    }
    dijkstra(s2,distu);
    dijkstra(t2,distv);
    dijkstra(s1,dists);
    vector<int> ord;
    for(int i=1;i<=n;i++)ord.emplace_back(i);
    sort(ord.begin(),ord.end(),[&](int i,int j){
        return dists[i]<dists[j];
    });
    for(int i=1;i<=n;i++){
        for(int x=0;x<2;x++){
            for(int y=0;y<2;y++){
                dp[i][x][y]=INF;
            }
        }
    }
    dp[s1][0][0]=0;
    for(int cur:ord){
        for(int x=0;x<2;x++){
            for(int y=0;y<2;y++){
                if(x==0){
                    dp[cur][1][y]=min(dp[cur][1][y],dp[cur][x][y]+distu[cur]);
                }
                if(y==0){
                    dp[cur][x][1]=min(dp[cur][x][1],dp[cur][x][y]+distv[cur]);
                }
            }
        }
        for(auto [to,w]:adj[cur]){
            if(dists[to]!=dists[cur]+w)continue;
            for(int x=0;x<2;x++){
                for(int y=0;y<2;y++){
                    dp[to][x][y]=min(dp[to][x][y],dp[cur][x][y]);
                }
            }
        }
    }
    cout << min(dp[t1][1][1],distu[t2]) << "\n";
}
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