Submission #304395

#	Time	Username	Problem	Language	Result	Execution time	Memory
304395		QAQAutoMaton	Counting Mushrooms (IOI20_mushrooms)	C++17	80.43 / 100	10 ms	384 KiB

mushrooms

#include "mushrooms.h"
#include<algorithm>
const int B=135;
int solve(int n,std::vector<int> &a){
	std::vector<int> b;
	int st=B+B+3,ans=0;
	while(st<n){
		int m=std::min(n-st,(int)a.size());
		b.clear();
		for(int i=0;i<m;++i){
			b.emplace_back(st+i);
			b.emplace_back(a[i]);
		}
		ans+=(use_machine(b)+1)>>1;
		st+=m;
	}
	return ans;
}
int count_mushrooms(int n) {
	std::vector<int> xA(0),xB(0);
	xA.emplace_back(0);
	if(n<=B){
		int ans=1;
		for(int i=1;i<n;++i){
			ans+=!use_machine({0,i});
		}
		return ans;
	}
	else{
		int x=!use_machine({0,1}),y=!use_machine({0,2});
		(x?xA:xB).emplace_back(1);
		(y?xA:xB).emplace_back(2);
		int s1,s2,w;
		if(x){s1=0,s2=1;w=0;}
		else if(y){s1=0;s2=2;w=0;}
		else{s1=1;s2=2;w=3;}
		if(n<=B+B+3){
			for(int i=3;i<n;i+=2){
				if(i+1==n){
					(!use_machine({0,i})?xA:xB).emplace_back(i);
				}
				else{
					int v=use_machine({s1,i,s2,i+1})^w;
					(v&2?xB:xA).emplace_back(i);
					(v&1?xB:xA).emplace_back(i+1);
				}
			}
			return xA.size();
		}
		else{
			for(int i=0;i<B;++i){
				int v=use_machine({s1,(i<<1)+3,s2,(i<<1)+4})^w;
				(v&2?xB:xA).emplace_back((i<<1)+3);
				(v&1?xB:xA).emplace_back((i<<1)+4);
			}
			if(xA.size()>xB.size()){
				return xA.size()+(n-B-B-3)-solve(n,xA);	
			}
			else{
				return xA.size()+solve(n,xB);	
			}
		}
	}
}

• Subtask 1: 80.427 / 100