Submission #1047066

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047066		MarwenElarbi	Counting Mushrooms (IOI20_mushrooms)	C++17	80.14 / 100	6 ms	852 KiB

mushrooms

#include <bits/stdc++.h>
using namespace std;
#include "mushrooms.h"
#define pb push_back
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int count_mushrooms(int n) {
	if(n==2) return 1+(1-use_machine({1,0}));
	vector<int> aa;
	aa.pb(0);
	vector<int> bb;
	int lst=3;
	vector<int> per;
	for (int i = 0; i < n; ++i) per.pb(i);
	shuffle(per.begin()+1,per.end(),rng);
	( use_machine({0,per[1]}) ? bb.pb(per[1]) : aa.pb(per[1]));
	( use_machine({0,per[2]}) ? bb.pb(per[2]) : aa.pb(per[2]));
	for (int i = 3; i+1 < min(n,284); i+=2)
	{
		if(aa.size()>=141||bb.size()>=141) break;
		lst=i+2;
		int cur;
		if(aa.size()>=2){
			cur=use_machine({per[i],aa[0],per[i+1],aa[1]});
			if(cur==0){
				aa.pb(per[i]);
				aa.pb(per[i+1]);
			}else if(cur==1){
				bb.pb(per[i]);
				aa.pb(per[i+1]);
			}else if(cur==2){
				aa.pb(per[i]);
				bb.pb(per[i+1]);
			}else if(cur==3){
				bb.pb(per[i]);
				bb.pb(per[i+1]);
			}	

		}
		else{
			cur=use_machine({per[i],bb[0],per[i+1],bb[1]});
			if(cur==0){
				bb.pb(per[i]);
				bb.pb(per[i+1]);
			}else if(cur==1){
				aa.pb(per[i]);
				bb.pb(per[i+1]);
			}else if(cur==2){
				bb.pb(per[i]);
				aa.pb(per[i+1]);
			}else if(cur==3){
				aa.pb(per[i]);
				aa.pb(per[i+1]);
			}
		}
	}
	int ans=aa.size();
	for (int i = lst; i < n; i+=140)
	{
		vector<int> cur;
		int k=0;
		for (int j = 0; j < min(n-i,140); ++j)
		{
			cur.pb(per[i+j]);
			cur.pb((aa.size()>bb.size() ? aa[k++] : bb[k++]));
		}
		int cnt=use_machine(cur);
		cnt++;
		ans+=(aa.size()<=bb.size() ? cnt/2 : cur.size()-k-cnt/2);
		if((cnt-1)%2) ((aa.size()>bb.size() ? bb.pb(per[i]) : aa.pb(per[i])));
	}
	return ans;
}

• Subtask 1: 80.1418 / 100