Submission #963177

#	Time	Username	Problem	Language	Result	Execution time	Memory
963177		HuyAT	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	243 ms	22496 KiB

commuter_pass

#include<bits/stdc++.h>

const int MaxN = 1e5 + 10;
const long long Inf = 1e18;

struct Data{
    long long vertex,w;
    bool operator > (const Data &other) const{
        return (w > other.w);
    }
};
std::vector<std::pair<int,int>> adj[MaxN + 1];
int n,m;
long long f[4][MaxN + 1],s,t,s1,t1,ans = Inf;
std::pair<long long,long long> minPath[MaxN + 1],minPath1[MaxN + 1];

bool vis[MaxN + 1];

void readData(){
    std::cin >> n >> m >> s >> t >> s1 >> t1;
    for(int i = 1;i <= m;++i){
        int u,v,w;
        std::cin >> u >> v >> w;
        adj[u].emplace_back(v,w);
        adj[v].emplace_back(u,w);
    }
}
void disjktra(int source,long long dist[]){
    std::fill(dist + 1,dist + n + 1,Inf);
    std::priority_queue<Data,std::vector<Data>,std::greater<Data>> pq;
    pq.push({source,0});
    dist[source] = 0;
    while(!pq.empty()){
        Data t = pq.top();
        pq.pop();
        if(t.w > dist[t.vertex]){
            continue;
        }
        for(std::pair<int,int> v : adj[t.vertex]){
            if(t.w + v.second < dist[v.first]){
                dist[v.first] = t.w + v.second;
                pq.push({v.first,dist[v.first]});
            }
        }
    }
}
void disjktra1(){
    std::fill(f[3] + 1,f[3] + n + 1,Inf);
    for(int i = 1;i <= n;++i){
        minPath[i] = {f[1][i],f[2][i]};
        minPath1[i] = {f[2][i],f[1][i]};
    }
    std::priority_queue<Data,std::vector<Data>,std::greater<Data>> pq;
    pq.push({s,0});
    f[3][s] = 0;
    while(!pq.empty()){
        Data t = pq.top();
        pq.pop();
        if(t.w > f[3][t.vertex]){
            continue;
        }
        for(std::pair<int,int> v : adj[t.vertex]){
            if(t.w + v.second < f[3][v.first]){
                f[3][v.first] = t.w + v.second;
                pq.push({v.first,f[3][v.first]});
                std::pair<long long,long long> first = {std::min(f[1][v.first],minPath[t.vertex].first),std::min(f[2][v.first],minPath[t.vertex].second)};
                std::pair<long long,long long> second = {std::min(f[2][v.first],minPath1[t.vertex].first),std::min(f[1][v.first],minPath1[t.vertex].second)};
                minPath[v.first] = first;
                minPath1[v.first] = second;
//                assert(std::min(first.first,first.second) > 0);
//                assert(std::min(second.first,second.second) > 0);

            }
            if(t.w + v.second == f[3][v.first]){
                std::pair<long long,long long> first = {std::min(f[1][v.first],minPath[t.vertex].first),std::min(f[2][v.first],minPath[t.vertex].second)};
                std::pair<long long,long long> second = {std::min(f[2][v.first],minPath1[t.vertex].first),std::min(f[1][v.first],minPath1[t.vertex].second)};
                minPath[v.first] = std::min(minPath[v.first],first);
                minPath1[v.first] = std::min(minPath1[v.first],second);
            }
        }
    }
}
void dfs(int u = t){
    vis[u] = true;
    ans = std::min(ans,minPath[u].first + minPath[u].second);
    ans = std::min(ans,minPath1[u].first + minPath1[u].second);
    for(std::pair<int,int> v : adj[u]){
        if(f[3][v.first] + v.second == f[3][u] && !vis[v.first]){
            dfs(v.first);
        }
    }
}
int main(){
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);std::cout.tie(nullptr);
    readData();
    disjktra(s1,f[1]);
    disjktra(t1,f[2]);
    disjktra1();
    dfs();
    ans = std::min(ans,f[2][s1]);
    std::cout << ans;
    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45