Submission #604635

#	Time	Username	Problem	Language	Result	Execution time	Memory
604635		rrrr10000	Counting Mushrooms (IOI20_mushrooms)	C++14	92.62 / 100	16 ms	720 KiB

mushrooms

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<ll,ll> P;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<bool> vb;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define REP(i,k,n) for(ll i=(ll)(k);i<(ll)(n);i++)
#define all(a) a.begin(),a.end()
#define fi first
#define se second
#define pb emplace_back
template<class T> void out(T a){cout<<a<<endl;}
#include "mushrooms.h"
int count_mushrooms(int n){
    if(n<=226){
        int ans=1;
        vector<int> ask(2);
        REP(i,1,n){
            ask[1]=i;
            int res=use_machine(ask);
            if(res==0)ans++;
        }
        return ans;
    }
    int B=167,f=0;
    if(B%2==0)B++;
    vi va,vb;va.pb(0);
    vi ord(n);
    rep(i,n)ord[i]=i;
    random_shuffle(ord.begin()+1,ord.end());
    {
        REP(I,1,3){
            ll i=ord[I];
            vector<int> ask(2,ord[0]);
            ask[1]=i;
            int res=use_machine(ask);
            if(res==0)va.pb(i);
            else vb.pb(i);
        }
        if(va.size()<vb.size()){
            swap(va,vb);f^=1;
        }
    }
    {
        for(ll I=3;I<B;I+=2){
            ll i=ord[I],j=ord[I+1];
            vector<int> ask(4);
            ask[1]=va[0];ask[3]=va[1];
            ask[0]=i;ask[2]=j;
            int res=use_machine(ask);
            if(res%2==0)va.pb(i);
            else vb.pb(i);
            if(res/2==0)va.pb(j);
            else vb.pb(j);
        }
        if(va.size()<vb.size()){
            swap(va,vb);f^=1;
        }
    }
    int ans=0;
    for(ll I=B;I<n;){
        vi al;
        REP(j,I,I+va.size())if(j<n)al.pb(ord[j]);
        I+=va.size();
        vector<int> ask(al.size()*2);
        rep(j,al.size())ask[j*2]=al[j];
        rep(j,al.size())ask[j*2+1]=va[j];
        int res=use_machine(ask);
        if(f==1)ans+=res/2;
        else ans+=al.size()-1-res/2;
        if(res%2==0)va.pb(al[0]);
        else vb.pb(al[0]);
        if(va.size()<vb.size()){
            swap(va,vb);f^=1;
        }
    }
    if(f)ans+=vb.size();
    else ans+=va.size();
    return ans;
}

• Subtask 1: 92.623 / 100