CF1406E Deleting Numbers

CF1406E Deleting Numbers

做法：

枚举所有小于等于n的素数：

分成两部分:

小于等于sqrt(n)时：

B询问一个素数，然后A询问，如果A询问结果为0，那么全删了，如果A询问结果为1，说明x是这个素数的倍数，按因数分解的素因子逆向枚举这个x。

大于sqrt(n)时：

分块A操作删一个块的素数，超过或者到最后询问一个A 1看看有没有删少了，删少了就在这个块里。
实现1：

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<climits>
#include<cstring>
#include<cassert>
#include<vector>
#include<map>
#include<queue>
#include<iterator>
#include<utility>
#include<algorithm>
//#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> pii;
#define mp make_pair
#define fi first
#define se second
#define All(x) (x).begin(),(x).end()
#define Y1 "YES"
#define N1 "NO"
#define ENDL '
'
#define count2(x) __builtin_popcount(x)
#define countleadingzero(x) __builtin_clz(x)
inline ll read(){//not solve LLONG_MIN LMAX=9,223,372,036,854,775,807
    ll s=0,w=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
    while(ch>='0' && ch<='9')s=s*10+ch-'0',ch=getchar();
    return s*w;
}
const int maxquery=1e4;//最大询问次数
const int PRSIZE=2e5;
int isprime[PRSIZE];
vector<int>primelist; //记录素数
vector<int>primeval[10000];
int n;
void init(){
	for(int i=2;i<=n;++i){
		isprime[i]=true;
	}
	for(int i=2;i<=n;++i){
		if(isprime[i]){
			int sz=primelist.size();
			primeval[sz].push_back(i);
			for(int j=2;j*i<PRSIZE;++j){
				if(isprime[j*i]!=false){
					isprime[j*i]=false;
					primeval[sz].push_back(j*i);
				}
			}
			primelist.push_back(i); 
		}
	}
	return ;
}
vector<int>block;//to solve primelist[query]>n
int main(){
	n=read();
	init();
	int allcnt=n;
	unsigned int querynum=0;
	bool finder=false;
	int i=1;
	for(i=1;i<maxquery;){
		if(querynum<primelist.size()&&primelist[querynum]<=sqrt(n)){
			int thisnum=primelist[querynum];
			{
			printf("B %d
",thisnum),++i;
			fflush(stdout);	
			}
			int deletenumber=read();
			allcnt-=deletenumber;
			cout<<"A "<<thisnum<<'
';
			fflush(stdout);
			int nowdeletednumber=read();
			if(nowdeletednumber!=0){
				int number=thisnum;
				int answer=thisnum;
				while(1){
					int rp=false;
					for(unsigned int ip=0;ip<primelist.size()&&primelist[ip]*number<=n;++ip){
						printf("B %d
",primelist[ip]*number),++i;
						fflush(stdout);
						int response=read();
						if(response==1){
							number=primelist[ip]*number;
							answer=max(answer,number);
							rp=true;
							break; 
						}
						if(response==0){
							rp=false;
						} 
					}
					if(rp==false)break;
				}
				if(answer!=0){
					{
						printf("C %d
",answer),++i;
						fflush(stdout);	
					}
					
					finder=true;
					break;	
				}
			}
			querynum++;
		}
		else if(querynum<primelist.size()&&primelist[querynum]<=n){
			//break;
			//choose 20 as block size
			int thisnum=primelist[querynum];
			{
				printf("B %d
",thisnum),++i;
				fflush(stdout);	
			}
			
			int deletenumber=read();
			allcnt-=1;
			block.push_back(thisnum);
			if(block.size()==100||querynum==primelist.size()-1){
				{
					printf("A 1
"),++i;
					fflush(stdout);	
				}
				
				int queryans=read();
				if(queryans>allcnt){
					bool checker=false;
					for(unsigned int iprime=0;iprime<block.size();++iprime){
						{
							printf("B %d
",block[iprime]),++i;
							fflush(stdout);	
						}
						int getnumber=read();
						if(getnumber==1){
							
							{
								printf("C %d
",block[iprime]),++i;
								fflush(stdout);	
							}
							checker=true;
							break;
						} 
					}
					if(checker){
						finder=true;
						break;
					}
				}
				block.clear();
			}
			querynum++;
		}
		else break;
	}
	if(finder==false){
		cout<<"C 1
";
		fflush(stdout);
	}
	return 0;
}

实现2：

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<climits>
#include<cstring>
#include<vector>
#include<map>
#include<queue>
#include<iterator>
#include<utility>
#include<algorithm>
//#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> pii;
#define mp make_pair
#define fi first
#define se second
#define All(x) (x).begin(),(x).end()
#define Y1 "YES"
#define N1 "NO"
#define ENDL '
'
#define count2(x) __builtin_popcount(x)
#define countleadingzero(x) __builtin_clz(x)
inline ll read(){//not solve LLONG_MIN LMAX=9,223,372,036,854,775,807
    ll s=0,w=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
    while(ch>='0' && ch<='9')s=s*10+ch-'0',ch=getchar();
    return s*w;
}
constexpr int SIZE=1e5+1;
constexpr int PRSIZE=1e4;//cnt=9592
int primelist[PRSIZE],pcnt=0;
bool isprime[SIZE];
int n;
//vector<int>primeval[PRSIZE];
void init(){
	for(int i=2;i<=n;++i) isprime[i]=true;
	for(int i=2;i<=n;++i){
		if(isprime[i]==true){
			primelist[pcnt++]=i;
			for(int j=2;j*i<=n;++j)
			isprime[i*j]=false;
		}
	}
}
inline int fpow(int a,int b){
	if(b==0) return 1;
	if(a==0) return 0;
	int ans=1,base=a;
	for(;b>0;b/=2){
		if(b&1)ans*=base;
		base=base*base;
	}
	return ans;
}
constexpr int BLOCKSIZE=98;//sqrt(9592)
int block[BLOCKSIZE],bcnt;
int main(){
	n=read();
	int sq=sqrt(double(n));
	init();
	int ans=1;
	int LLCNT=n;
	for(int i=0;i<pcnt;++i){
		int now=primelist[i];
		int answerA,answerB;
		if(primelist[i]<=sq){
			cout<<"B "<<now<<endl;
			cin>>answerB;//!=0
			LLCNT-=answerB;
			cout<<"A "<<now<<endl;
			cin>>answerA;
			int factor=1;
			if(answerA!=0){
				LLCNT+=answerA;
				int base=now;
				factor=base;
				for(int j=2;base*now<=n;++j){
					base*=now;
					cout<<"A "<<base<<endl;
					cin>>answerA;
					if(answerA==1)
					factor=base;
					else break;
				}
				ans*=factor;
			}
		}
		else if(ans<=sqrt(n)){
			cout<<"B "<<now<<endl;
			block[bcnt++]=now;
			cin>>answerB;
			LLCNT-=answerB;
			if(bcnt==BLOCKSIZE||i==pcnt-1){
				cout<<"A "<<1<<endl;
				int realcnt;
				cin>>realcnt;
				if(realcnt>LLCNT){
					for(int ib=0;ib<bcnt;++ib){
						cout<<"A "<<block[ib]<<endl;
						cin>>answerA;
						if(answerA==1){
							ans*=block[ib];
							bcnt=0;
							break;
						}
					}
				}
				bcnt=0;
			}
		}
		else break;
	}
	cout<<"C "<<ans<<endl;
	return 0;
}