Submission #919613

#	Time	Username	Problem	Language	Result	Execution time	Memory
919613		noyancanturk	Cyberland (APIO23_cyberland)	C++17	100 / 100	1132 ms	12624 KiB

cyberland

#pragma GCC optimize("O3,unroll-loops")
#ifndef Local
#include "cyberland.h"
#endif
#include <bits/stdc++.h>
using namespace std;

const int lim=1e5+10;

const double inf=2e18;


using pii=pair<int,int>;
using pdi=pair<double,int>;
vector<pii> v[lim];
 
bool vis[lim];
int n,m,k,h;
void dfs(int node){
    vis[node]=1;
    if(node==h)return;
    for(auto [f,s]:v[node]){
        if(!vis[f]){
            dfs(f);
        }
    }
}

double solve(int N, int M, int K, int H, std::vector<int> x, std::vector<int> y, std::vector<int> c, std::vector<int> arr) {
    n=N,m=M,k=min(K,100),h=H;
    for(int i=0;i<n;i++){
        vis[i]=0;
        v[i].clear();
    }
    for(int i=0;i<m;i++){
        v[x[i]].push_back({y[i],c[i]});
        v[y[i]].push_back({x[i],c[i]});
    }
    dfs(0);
    double *dist[2];
    dist[0]=new double[n];
    dist[1]=new double[n];
    //for(int i=0;i<n;i++)cerr<<vis[i]<<"\n";
    for(int i=0;i<n;i++){
        dist[0][i]=(arr[i]||!vis[i])?inf:0;
    }
    priority_queue<pdi,vector<pdi>,greater<pdi>>pq;
    for(int i=0;i<n;i++){
        if(!arr[i]&&vis[i]){
            pq.push({0,i});
        }
    }
    dist[0][0]=0;
    pq.push({0,0});
    //else cerr<<arr[0]<<"\n";
    double ans=inf;
    for(int rp=0;rp<min(k+1,100);rp++){
        /*
        for(int i=0;i<n;i++){
            cerr<<dist[0][i]<<" ";
        }cerr<<"\n";
        */
        for(int i=0;i<n;i++){
            dist[1][i]=inf;
        }
        while(pq.size()){
            auto nn=pq.top();
            pq.pop();
            double cost=nn.first;
            int node=nn.second;
            /*
            cerr<<node<<" "<<cost<<" visited\n";
            cerr<<cost<<" "<<dist[0][node]<<"\n";
            */
            if(dist[0][node]<cost||node==h)continue;
            //cerr<<"ok\n";
            for(auto j:v[node]){
                //cerr<<j.first<<" "<<cost+j.second<<"\n";
                //if(j.first==4&&cost+j.second==2)cerr<<node<<"\n";
                if(arr[j.first]&&cost+j.second<dist[0][j.first]){
                    dist[0][j.first]=cost+j.second;
                    pq.push({cost+j.second,j.first});

                    //cerr<<node<<" inserted "<<j.first<<" "<<cost+j.second<<"\n";
                    //cerr<<dist[0][j.first]<<" "<<cost+j.second<<"\n";
                }
                if(arr[j.first]==2&&(cost+j.second)/2<dist[1][j.first]){
                    dist[1][j.first]=min(dist[1][j.first],(cost+j.second)/2);
                }
                //else cerr<<cost<<" "<<j.second<<" "<<dist[0][j.first]<<"\n";
            }
        }
        /*
        for(int i=0;i<n;i++){
            cerr<<dist[0][i]<<" ";
        }cerr<<"\n";
        for(int i=0;i<n;i++){
            cerr<<dist[1][i]<<" ";
        }cerr<<"\n";
        */
        //cerr<<h<<"\n";
        for(int i=0;i<n;i++){
            if(dist[1][i]!=inf)pq.push({dist[1][i],i});
        }
        ans=min(ans,dist[0][h]);
        ans=min(ans,dist[1][h]);
        //cerr<<ans<<"\n";
        swap(dist[0],dist[1]);
    }
    /*
    for(int i=0;i<n;i++){
        cerr<<dist[0][i]<<" ";
    }cerr<<"\n";
    */
    if(ans==inf)return -1;
    return ans;
}

#ifdef Local
int main(){
    freopen(".in","r",stdin);
    freopen(".out","w",stdout);
    int t;
    cin>>t;
    while(t--){
        cin>>n>>m>>k>>h;
        vector<int>x,y,z,arr;
        for(int i=0;i<n;i++){
            int rr;
            cin>>rr;
            arr.push_back(rr);
        }
        for(int i=0;i<m;i++){
            int xx,yy,zz;
            cin>>xx>>yy>>zz;
            x.push_back(xx);
            y.push_back(yy);
            z.push_back(zz);
        }
        cout<<setprecision(30)<<(double)solve(n,m,k,h,x,y,z,arr)<<"\n";
    }
    //cout<<solve(6, 7, 1, 4, {0, 0, 2, 1, 1, 3, 4}, {1, 2, 3, 2, 3, 4, 5}, {2, 3, 4, 2, 5, 3, 2}, {1, 0, 2, 1, 1, 0})<<"\n";
    //cout<<solve(3,3,2,2,{0,1,2},{1,2,0},{2,2,3},{1,2,1})<<"\n";
}
#endif

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 13 / 13
• Subtask 4: 19 / 19
• Subtask 5: 7 / 7
• Subtask 6: 16 / 16
• Subtask 7: 29 / 29
• Subtask 8: 3 / 3