Submission #881637

#	Time	Username	Problem	Language	Result	Execution time	Memory
881637		nikd	Dreaming (IOI13_dreaming)	C++17	0 / 100	30 ms	14168 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
#define MAXN 100001
using namespace std;

int maxpar1[MAXN];
int node1[MAXN];
int maxpar2[MAXN];
int maxlength[MAXN];
int maxbyp[MAXN];
bool vis[MAXN];
int tree[MAXN];
int cont;
vector<int> mintree;
vector<pair<int, int>> adj[MAXN];
void dfs1(int v, int p){   
    tree[v]=cont;
    vis[v]=true;
    if(adj[v].size()==1&&p!=v){
        maxpar1[v]=0;
        maxpar2[v]=0;
    }
    else{
        for (auto u : adj[v]) {
            if (u.first != p){
                dfs1(u.first, v);
                if(maxpar1[v]<maxpar1[u.first]+u.second){
                    maxpar2[v]=maxpar1[v];
                    maxpar1[v]=maxpar1[u.first]+u.second;
                    node1[v]=u.first;
                }
                else if(maxpar2[v]<maxpar1[u.first]+u.second){
                    maxpar2[v]=maxpar1[u.first]+u.second;
                }
                
            }
        }
    }
    maxlength[v]=maxpar1[v];
}
void dfs2(int v, int p, int d){   
    vis[v]=true;
    if(v!=p){
        if(node1[p]!=v){
            maxbyp[v]= max(maxpar1[p]+d, maxbyp[p]+d);
            maxlength[v]=max(maxlength[v], maxbyp[v]);
        }
        else{
            
            maxbyp[v]=max(maxpar2[p]+d, maxbyp[p]+d);
            maxlength[v]=max(maxlength[v], maxbyp[v]);
        }
    }
    for (auto u : adj[v]) {
        if (u.first != p){
            dfs2(u.first, v, u.second);
            
        }
    }
    
}


int travelTime(int N, int M, int L, int A[], int B[], int T[]){
    for(int i = 0; i<M; i++){
        adj[A[i]].push_back({B[i], T[i]});
        adj[B[i]].push_back({A[i], T[i]});
    }
    for(int i = 0; i<N; i++){
        maxpar1[i]=0;
        maxpar2[i]=0;
        maxlength[i]=0;
        maxbyp[i]=0;
        vis[i]=false;
    }
    cont =0;
    for(int i =0; i<N; i++){
        if(!vis[i]){
            mintree.push_back(INT_MAX);
            dfs1(i,i);
            cont++;
        }
    }
    for(int i =0; i<N; i++) vis[i]=false;
    for(int i =0; i<N; i++){
        if(!vis[i]){
            dfs2(i, i, 0);
        }
    }
    int maxbest1=-1;
    int maxbest2=-1;
    int maxbest3=-1;
    for(int i =0; i<N; i++){
        if(maxlength[i]<mintree[tree[i]]){
            mintree[tree[i]]=maxlength[i];
            
        }
    }
    for(int j: mintree){
        if(j>maxbest1){
            maxbest3=maxbest2;
            maxbest2=maxbest1;
            maxbest1=j;
            
        }
        else if(j>maxbest2){
            maxbest3=maxbest2;
            maxbest2=j;
        }
        else if(j>maxbest3){
            maxbest3=j;
        }
    }
    int sol;
    if(maxbest3!=-1){
        sol =max(maxbest1+L+maxbest2, maxbest2+maxbest3+2*L);
    }
    else sol=maxbest1+L+maxbest2;
    return sol;


}

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