Submission #900608

#	Time	Username	Problem	Language	Result	Execution time	Memory
900608		JakobZorz	Dreaming (IOI13_dreaming)	C++17	77 / 100	1047 ms	47268 KiB

dreaming

#include"dreaming.h"
#include<iostream>
#include<vector>
#include<algorithm>
#include<map>
using namespace std;
typedef long long ll;

vector<pair<ll,ll>>nodes[100000];
bool vis[100000];
vector<ll>node_list;

void dfs(ll node){
    if(vis[node])
        return;
    vis[node]=true;
    node_list.push_back(node);
    for(auto ne:nodes[node])
        dfs(ne.first);
}

map<pair<ll,ll>,pair<ll,ll>>dp;
pair<ll,ll>get_max_dist(ll node,ll prev){
    if(dp.count({node,prev}))
        return dp[{node,prev}];
    
    pair<ll,ll>res={0,0};
    for(auto ne:nodes[node]){
        if(ne.first==prev)
            continue;
        
        {
            ll curr=get_max_dist(ne.first,node).first+ne.second;
            if(curr>=res.first){
                res.second=res.first;
                res.first=curr;
            }else if(curr>res.second){
                res.second=curr;
            }
        }
    }
    dp[{node,prev}]=res;
    return res;
}

pair<ll,ll> get_diameter(ll root){
    node_list.clear();
    dfs(root);
    /*cout<<"- ";
    for(int i:node_list)
        cout<<i<<" ";
    cout<<"\n";*/
    
    ll res=1e18,diam=0;
    for(ll node:node_list){
        //cout<<node<<": "<<get_max_dist(node,node)<<"\n";
        auto r=get_max_dist(node,node);
        res=min(res,r.first);
        diam=max(diam,r.first+r.second);
    }
    return {res,diam};
}

int travelTime(int N,int M,int L,int A[],int B[],int T[]){
    for(ll i=0;i<M;i++){
        nodes[A[i]].emplace_back(B[i],T[i]);
        nodes[B[i]].emplace_back(A[i],T[i]);
    }
    
    vector<ll>dists;
    ll diam=0;
    for(ll i=0;i<N;i++)
        if(!vis[i]){
            auto r=get_diameter(i);
            dists.push_back(r.first);
            diam=max(diam,r.second);
        }
    
    sort(dists.begin(),dists.end());
    reverse(dists.begin(),dists.end());
    if(dists.size()==1)
        return max(dists[0],diam);
    else if(dists.size()==2)
        return max(dists[0]+dists[1]+L,diam);
    else
        return max(max(dists[0]+dists[1]+L,dists[1]+dists[2]+2*L),diam);
}

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 0 / 23