Submission #227144

#	Time	Username	Problem	Language	Result	Execution time	Memory
227144		MKopchev	Meetings (JOI19_meetings)	C++14	100 / 100	1179 ms	3320 KiB

meetings

#include <bits/stdc++.h>
#include "meetings.h"
using namespace std;
/*
void Bridge(int a,int b)
{
    cout<<a<<" "<<b<<endl;
}
int Query(int a,int b,int c)
{
    cout<<a<<" "<<b<<" "<<c<<endl;
    int ret;
    cin>>ret;
    return ret;
}
*/
map< pair< pair<int,int>,int>,int> seen;

int ask(int a,int b,int c)
{
    if(a==b)return a;
    if(a==c)return a;
    if(b==c)return b;

    if(a>b)swap(a,b);
    if(a>c)swap(a,c);
    if(b>c)swap(b,c);

    pair< pair<int,int>,int> state={{a,b},c};

    if(seen.count(state))return seen[state];

    int d=Query(a,b,c);

    seen[state]=d;

    return d;
}
const int nmax=2e3+42;

vector< pair<int,int> > output;

void add_path(int a,int b)
{
    output.push_back({a,b});
}
int n;

mt19937 rng(42);

int a_now,b_now;

bool cmp(int u,int v)
{
    return ask(a_now,u,v)==u;
}
void solve(vector<int> active)
{
    if(active.size()<=1)return;

    shuffle(active.begin(),active.end(),rng);

    int a=active[rng()%active.size()],b=active[rng()%active.size()];

    while(a==b)a=active[rng()%active.size()],b=active[rng()%active.size()];

    //cout<<"a= "<<a<<" b= "<<b<<endl;

    vector<int> on_path={},remain={};

    for(auto k:active)
        if(k!=a&&k!=b)
        {
            if(ask(a,k,b)==k)on_path.push_back(k);
            else remain.push_back(k);
        }

    a_now=a;
    b_now=b;

    sort(on_path.begin(),on_path.end(),cmp);

    //cout<<a<<" ";for(auto k:on_path)cout<<k<<" ";cout<<b<<endl;

    on_path.insert(on_path.begin(),a);

    on_path.push_back(b);

    for(int i=1;i<on_path.size();i++)
        add_path(on_path[i-1],on_path[i]);

    map<int, vector<int> > would_be={};

    for(auto k:remain)
        would_be[ask(a,k,b)].push_back(k);

    for(auto k:would_be)
    {
        int node=k.first;

        vector<int> on_subtree=k.second;

        if(on_subtree.size()==0)continue;

        vector< vector<int> > subtrees={};

        for(auto w:on_subtree)
        {
            bool taken=0;

            for(int i=0;i<subtrees.size();i++)
                if(ask(node,subtrees[i].back(),w)!=node)
                {
                    subtrees[i].push_back(w);
                    taken=1;
                    break;
                }
            if(taken==0)
            {
                subtrees.push_back({w});
            }
        }

        for(auto subtree:subtrees)
        {
            solve(subtree);

            int sub_root=subtree[0];

            for(int j=1;j<subtree.size();j++)
                if(sub_root!=node)sub_root=ask(sub_root,node,subtree[j]);

            add_path(sub_root,node);
        }
    }
}
void Solve(int n)
{
    vector<int> active={};

    for(int i=0;i<n;i++)
        active.push_back(i);

    solve(active);

    for(auto k:output)
    {
        if(k.first>k.second)swap(k.first,k.second);

        Bridge(k.first,k.second);
    }
}
/*
int main()
{
    Solve(5);
}
*/

Compilation message (stderr)

meetings.cpp: In function 'void solve(std::vector<int>)':
meetings.cpp:89:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=1;i<on_path.size();i++)
                 ~^~~~~~~~~~~~~~~
meetings.cpp:111:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int i=0;i<subtrees.size();i++)
                         ~^~~~~~~~~~~~~~~~
meetings.cpp:130:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j=1;j<subtree.size();j++)
                         ~^~~~~~~~~~~~~~~

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