Submission #621179

#	Time	Username	Problem	Language	Result	Execution time	Memory
621179		KLPP	Counting Mushrooms (IOI20_mushrooms)	C++14	75.84 / 100	12 ms	324 KiB

mushrooms

#include "mushrooms.h"
#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define trav(a,v) for(auto a:v)
typedef long long int lld;
int K;
int answer[1000];
int count_mushrooms(int n) {
	if(n<220){
		int ans=1;
		rep(i,1,n){
			vector<int> V;
			V.push_back(0);
			V.push_back(i);
			int u=use_machine(V);
			ans+=1-u;
		}
		return ans;
	}
	K=min(200,n-1);
	vector<int> zeros;
	vector<int> ones;
	answer[0]=0;
	zeros.push_back(0);
	rep(i,1,3){
		vector<int> V;
		V.push_back(0);
		V.push_back(i);
		int u=use_machine(V);
		answer[i]=u;
		if(u==1)ones.push_back(i);
		else zeros.push_back(i);
	}
	
	int x,y;
	if(zeros.size()>1)x=zeros[0],y=zeros[1];
	else x=ones[0],y=ones[1];
	rep(i,3,K+1){
		vector<int> V;
		V.push_back(x);
		V.push_back(i);
		V.push_back(y);
		V.push_back(i+1);
		int u=use_machine(V);
		answer[i]=u/2;
		if(answer[x])answer[i]^=1;
		answer[i+1]=u%2;
		if(answer[x])answer[i+1]^=1;
		if(answer[i]==1)ones.push_back(i);
		else zeros.push_back(i);
		if(answer[i+1]==1)ones.push_back(i+1);
		else zeros.push_back(i+1);
		i++;
	}
	int revert=false;
	if(zeros.size()<ones.size()){
		swap(zeros,ones);
		revert=true;
	}
	/*trav(a,ones)cout<<a<<" ";
	cout<<endl;
	trav(a,zeros)cout<<a<<" ";
	cout<<endl;*/
	vector<int> analyse;
	int cnt=0;
	int ans=0;
	rep(i,0,K+1)ans+=(answer[i]==0);
	rep(i,K+1,n){
		analyse.push_back(i);
		analyse.push_back(zeros[cnt]);
		//cout<<zeros[cnt]<<endl;
		cnt++;
		if(i==n-1 || cnt==zeros.size()){
			//cout<<cnt<<" "<<zeros.size()<<endl;
			int u=use_machine(analyse);
			
			if(u%2==1)u++;
			if(revert){
				ans+=u/2;
			}else{
				ans+=analyse.size()/2-u/2;
			}
			analyse.clear();
			cnt=0;
		}
	}
	return ans;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:74:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |   if(i==n-1 || cnt==zeros.size()){
      |                ~~~^~~~~~~~~~~~~~

• Subtask 1: 75.8389 / 100