Submission #680233

#	Time	Username	Problem	Language	Result	Execution time	Memory
680233		abcvuitunggio	Relay Marathon (NOI20_relaymarathon)	C++17	100 / 100	4264 ms	125900 KiB

RelayMarathon

#include <bits/stdc++.h>
using namespace std;
const int INF=1e9+10;
int a[100001],d[100001],ch[100001],n,m,k,u,v,w,res=INF*2;
vector <pair <int, int>> ke[100001];
vector <int> ve[4];
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int f(int s, int e){
    priority_queue <pair <int, int>, vector <pair <int, int>>, greater <pair <int, int>>> q;
    for (int i=1;i<=n;i++){
        d[i]=INF;
        ch[i]=0;
    }
    for (int i:ve[s]){
        d[i]=0;
        q.push({0,i});
    }
    for (int i:ve[e])
        ch[i]=1;
    while (!q.empty()){
        auto [du,u]=q.top();
        q.pop();
        if (ch[u])
            return du;
        if (du!=d[u])
            continue;
        for (auto [v,w]:ke[u])
            if (d[v]>d[u]+w){
                d[v]=d[u]+w;
                q.push({d[v],v});
            }
    }
    return INF;
}
int main(){
    ios_base::sync_with_stdio(NULL);cin.tie(nullptr);
    cin >> n >> m >> k;
    while (m--){
        cin >> u >> v >> w;
        ke[u].push_back({v,w});
        ke[v].push_back({u,w});
    }
    for (int i=1;i<=k;i++)
        cin >> a[i];
    chrono::milliseconds ms(3000);
    chrono::time_point<chrono::system_clock> end=chrono::system_clock::now()+ms;
    while (chrono::system_clock::now()<end){
        shuffle(a+1,a+k+1,rd);
        for (int i=0;i<4;i++)
            ve[i].clear();
        for (int i=1;i<=k;i++)
            ve[rd()%4].push_back(a[i]);
        res=min(res,f(0,1)+f(2,3));
    }
    cout << res;
}

• Subtask 1: 5 / 5
• Subtask 2: 12 / 12
• Subtask 3: 25 / 25
• Subtask 4: 58 / 58