Submission #978682

#	Time	Username	Problem	Language	Result	Execution time	Memory
978682		happy_node	Meetings (JOI19_meetings)	C++17	0 / 100	197 ms	262144 KiB

meetings

#include "meetings.h"
#include <bits/stdc++.h>
using namespace std;

const int MX=2005;

set<pair<int,int>> edges;

bool used[MX], vis[MX];
int sz[MX];
int N;

vector<int> adj[MX];

int getSize(int v, int p) {
        sz[v]=1;
        for(auto u:adj[v]) {
                if(u!=p && !used[u]) {
                        sz[v]+=getSize(u,v);
                }
        }
        return sz[v];
}

int getCen(int v, int p, int s) {
        for(auto u:adj[v]) {
                if(u!=p && 2*sz[u]>s && !used[u]) {
                        return getCen(u,v,s);
                }
        }
        return v;
}

int que(int u, int v, int w) {
        // cout<<"ask "<<u<<" "<<v<<" "<<w<<endl;
        // we can memo here
        return Query(u,v,w);
}

void cdc(int v, int x) {
        int s=getSize(v,v);
        int cen=getCen(v,v,s);
        getSize(cen,cen);
        used[cen]=true;

        // cout<<"at cen : "<<cen<<endl;

        bool fnd=0;

        for(auto u:adj[cen]) {
                if(used[u]) continue;
                if(que(cen,u,x)!=cen) {
                        fnd=1;
                        if(sz[u]>1)
                                cdc(u,x);
                        else {
                                int k=que(cen,u,x);
                                vis[k]=true;

                                // cout<<"add "<<k<<" "<<cen<<" "<<u<<" "<<x<<endl;

                                if(k!=cen) edges.insert({min(cen,k),max(cen,k)});
                                if(k!=u) edges.insert({min(u,k),max(u,k)});
                                if(k!=x) edges.insert({min(x,k),max(x,k)});
                        }

                        break;
                }
        }

        if(!fnd) {
                // cout<<"add "<<cen<<" "<<x<<endl;
                vis[x]=true;
                edges.insert({min(cen,x),max(cen,x)});
        }
}

void prep() {
        for(int i=0;i<N;i++) {
                used[i]=false;
                adj[i].clear();
        }
        for(auto [u,v]:edges) {
                adj[u].push_back(v);
                adj[v].push_back(u);
        }
}

void Solve(int _N) {
        N=_N;
                        
        int k=que(0,1,2);
        vis[0]=true;
        vis[1]=true;
        vis[2]=true;

        vis[k]=true;
        if(k!=0) edges.insert({min(0,k),max(0,k)});
        if(k!=1) edges.insert({min(1,k),max(1,k)});
        if(k!=2) edges.insert({min(2,k),max(2,k)});

        for(int i=3;i<N;i++) {
                if(vis[i]) continue;
                prep();
                cdc(0,i);
        }
        
        for(auto [u,v]:edges) {
                // cout<<"final: "<<u<<" "<<v<<endl;
                if(u>v) swap(u,v);
                Bridge(u,v);
        }
}

• Subtask 1: 0 / 7
• Subtask 2: 0 / 10
• Subtask 3: 0 / 12
• Subtask 4: 0 / 71