Submission #1032369

#	Time	Username	Problem	Language	Result	Execution time	Memory
1032369		hotboy2703	Counting Mushrooms (IOI20_mushrooms)	C++17	100 / 100	6 ms	600 KiB

mushrooms

#include "mushrooms.h"
#include<bits/stdc++.h>
using namespace std;
using ll = int;
#define pll pair <ll,ll>
#define fi first
#define se second
#define MP make_pair
#define sz(a) (ll((a).size()))
#define BIT(mask,i) (((mask) >> (i))&1)
#define MASK(i) (1LL<<(i))
ll use(vector <ll> tmp){
	// for (auto x:tmp)cout<<x<<' ';
	// cout<<endl;
	return use_machine(tmp);
}
int count_mushrooms(int n) {
	if (n<=5){
		ll res = 1;
		for (ll i = 1;i < n;i ++)if (use({0,i})==0)res++;
		return res;
	}
	vector <ll> c[2];
	c[0].push_back(0);
	c[use({0,1})].push_back(1);
	c[use({0,2})].push_back(2);
	{
		ll id = 0;
		if (sz(c[1]) > sz(c[0]))id = 1;
		ll tmp = use({3,c[id][0],4,c[id][1]});
		c[id ^ (tmp%2)].push_back(3);
		c[id ^ (tmp/2)].push_back(4);
	}
	// for (auto x:c[0])cout<<x<<' ';
	// cout<<'\n';
	// for (auto x:c[1])cout<<x<<' ';
	// cout<<'\n';
	ll ptr = 5;
	ll res = 0;
	while (ptr < n){
		if (max(sz(c[0]),sz(c[1])) >= 100){
			ll id = 0;
			if (sz(c[1]) > sz(c[0]))id = 1;
			vector <ll> tmp;
			for (ll j = 0;j < sz(c[id]) && ptr < n;j ++,ptr++){
				tmp.push_back(c[id][j]);
				tmp.push_back(ptr);
			}
			ll cur = use(tmp);
			if (cur%2)c[1-id].push_back(tmp.back());
			else c[id].push_back(tmp.back());
			if (id==1)res += cur/2;
			else res += sz(tmp)/2 - (cur/2+1);
		}
		else{
			ll id = 0;
			if (sz(c[1]) > sz(c[0]))id = 1;
			if (ptr + 4 < n){
				ll tmp = use({ptr,c[id][0],ptr+1,c[id][1],ptr+2,c[id][2]});
				c[id^BIT(tmp,0)].push_back(ptr);
				tmp-=tmp%2;
				// cout<<tmp<<endl;
				if (tmp==2){
					if (sz(c[1-id]) < 2){
						tmp = use({ptr+1,c[id][0],ptr+2,c[id][1]});
						c[id ^ BIT(tmp,0)].push_back(ptr+1);
						c[id ^ BIT(tmp,1)].push_back(ptr+2);
						ptr+=3;
					}
					else{
						tmp = use({c[!id][0],ptr+1,c[!id][1],c[id][0],ptr+2,c[id][1],ptr+3,c[id][2],ptr+4});
						tmp--;
						// cout<<ptr<<' '<<tmp<<' '<<id<<endl;
						c[id^BIT(tmp,0)].push_back(ptr+4);
						c[id^BIT(tmp,1)].push_back(ptr+3);
						c[id^BIT(tmp,2)].push_back(ptr+2);
						c[1^id^BIT(tmp,2)].push_back(ptr+1);
						ptr+=5;
					}
				}
				else{
					c[id^(tmp>0)].push_back(ptr+1);
					c[id^(tmp>0)].push_back(ptr+2);
					ptr+=3;
				}
			}
			else if (ptr + 1 < n){
				ll tmp = use({ptr,c[id][0],ptr+1,c[id][1]});
				c[id ^ BIT(tmp,0)].push_back(ptr);
				c[id ^ BIT(tmp,1)].push_back(ptr+1);
				ptr+=2;
			}
			else{
				c[use({0,ptr})].push_back(ptr);
				ptr++;
			}
		}
	}
	// for (auto x:c[0])cout<<x<<' ';
	// cout<<'\n';
	// for (auto x:c[1])cout<<x<<' ';
	// cout<<'\n';
	res += sz(c[0]);
	return res;
}

• Subtask 1: 100 / 100