素数对

1

wuhaolin1 LV 10 @ 2025-2-10 21:04:02

#include using namespace std; int n,cnt; bool check(int a){ for(int i=2;i*i<=a;i++){ if(a%i0)return false; } return true; } int main(){ cin>>n; for(int i=2;i<=n;i++){ if(i+2<=n&&check(i)&&check(i+2)){ cout<<i<<" "<<i+2<<endl; cnt=1; } } if(cnt0)cout<<"empty"; return 0;

1. 1. 1. 1. }***
1. 1. 1. 1. [ ] 2. | col1**** | col2 | col3 | | --- | --- | --- | | | | | | | | |***

1

Lawrence劳伦斯 LV 10 @ 2023-9-8 20:18:14

#include <bits/stdc++.h>
using namespace std;
int n;
bool c(int x)
{
	for(int i=2;i*i<=x;i++)
	{
		if(x%i==0)
		{
			return 0;
		}
	}
	return 1;
}
int main()
{
	cin>>n;
	for(int i=5;i<=n;i++)
	{
		if(c(i)&&c(i-2))
		{
			cout<<i-2<<" "<<i<<endl;
		}
	}
	if(n<5)
	{
		cout<<"empty";
	}
    return 0;
}

dongliyang @ 2024-8-30 18:10:59

有问题，1在bool函数里会怎样

1

lichengjun LV 10 @ 2023-3-28 18:33:52

普通做就行，不用紧张

#include<iostream>
using namespace std;
int n,cnt;
bool check(int a){
	for(int i=2;i*i<=a;i++){
		if(a%i==0)return false;
	}
	return true;
}
int main(){
	cin>>n;
	for(int i=2;i<=n;i++){
  		if(i+2<=n&&check(i)&&check(i+2)){
			cout<<i<<" "<<i+2<<endl;
			cnt=1;
		}
	}
	if(cnt==0)cout<<"empty";
	return 0;
}

dongliyang @ 2024-8-30 18:09:47

有问题，1在bool函数里会怎样

0

陈儒乐 LV 9 @ 2022-7-9 11:55:34

/crl(陈儒乐)/

#include <math.h>

#include <stdio.h>

#include <iostream>

#include <iomanip>

using namespace std;

int main()
{
	int n ,sum = 0;
	cin >> n;
	for(int i = 3 ; i <= n-2 ;i+=2)
	{
		int flag = 1;
		for(int j = 3; flag && j*j <= i ; j++)
			if(i%j == 0)
				flag = 0;

		int k = i + 2;
		for(int j = 3; flag && j*j <= k ; j++)
			if(k%j == 0)
				flag = 0;
		if(flag)
		{
			sum++;
			cout << i << " " << k << endl;
		}
	}
	if(sum == 0)
		cout << "empty\n";
	return 0;
}

dongliyang @ 2024-8-30 18:10:06

有问题，1在bool函数里会怎样

-1

liujinhao LV 8 @ 2024-9-21 18:37:12

#include<bits/stdc++.h> using namespace std; int cheak(int n){ if(n1) return 0; for(int i=2;i<n;i++){ if(n%i0){ return 0; } } return 1; } int main(){ int a[10000]={},n,cnt=0,flag=0; cin>>n; for(int i=1;i<=n;i++){ if(cheak(i)){ a[cnt]=i; cnt++; } } for(int i=1;i<cnt-1;i++){ if(a[i+1]-a[i]2){ cout<<a[i]<<" "<<a[i+1]<<endl; flag=1; } } if(flag0){ cout<<"empty"; } }

-1

linsiyuan LV 8 @ 2024-5-26 21:47:26

#include
using namespace std;
int check(int n){
	if(n==1){
		return 0;
	}
	for(int i=2;i<n;i++){
		if(n%i==0){
			return 0;
		}
	}
	return 1;
	
}
int main()
{
	int a[10000]={},n,cnt=1,flag=0;
	cin>>n;
	for(int i=1;i<=n;i++){
		if(check(i)){
			a[cnt]=i;
			cnt++;
		}
	} 	
	for(int i=1;i<cnt-1;i++){
		if(a[i+1]-a[i]==2){
			cout<<a[i]<<" "<<a[i+1]<<endl;
			flag=1;
		}
	} 
	if(flag==0) cout<<"empty";
	return 0;	
}

-1

gongyuting LV 3 @ 2024-3-17 16:31:59

#include<bits/stdc++.h> using namespace std; int f1(int n){ for(int i=2;i<=sqrt(n);i++) if(n%i==0)return 0; return 1; } int main(){ int n,sum=0; cin>>n; for(int i=2;i<=n;i++){ if(f1(i)==1&&f1(i+2)1&&i+2<=n){ sum++; cout<<i<<" "<<i+2<<endl; } }if(sum0)cout<<"empty"; }

dongliyang @ 2024-8-30 18:10:23

有问题，1在bool函数里会怎样
dongliyang @ 2024-8-30 18:10:43

@ bool是int

-1

liyaorong LV 6 @ 2023-12-20 20:11:59

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
const int INF=0x3f3f3f3f;
int n;
bool flag;

bool isPrime(int x){
	if(x<2) return 0;
	for(int i=2;i*i<=x;i++)
		if(x%i==0)
			return 0;
	return 1;
}
int main(){
	cin>>n;
	for(int i=2;i<=n;i++){
		if(isPrime(i)&&isPrime(i+2)&&i+2<=n){
			flag=1;
			cout<<i<<" "<<i+2<<endl;
		}
	}
	if(flag==0)
		cout<<"empty";
		
	return 0;
}

-1

zhangxuanju LV 7 @ 2023-12-20 20:03:24

#include<bits/stdc++.h>
using namespace std;
const int N=1e4+10;
int n,flag;
bool f(int x){
	if(x<2) return 0;
	for(int i=2;i<=sqrt(x);i++) if(x%i==0) return 0;
	return 1;
}
int main()
{
	cin>>n;
	for(int i=2;i<=n;i++){
		if(f(i)&&f(i+2)&&i+2<=n){
			flag=1;
			cout<<i<<" "<<i+2<<endl;
		}
	}
	if(!flag)
		cout<<"empty";
	return 0;
}

-1

zengzhiyuan LV 9 @ 2023-6-13 21:36:12

#include <bits/stdc++.h>//直接使用万能头
using namespace std;
#define ll long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
const int MOD = 100000007;
bool empty = true;
bool is_prime(ll n){//检测质数的函数
	for(ll i = 2;i * i <= n;i++){
		if(n % i == 0){
			return false;
		}
	}
	return true;
}
bool check(ll a,ll b){
	empty = false;
	
	if(not is_prime(a)) return false;
	if(not is_prime(b)) return false;
	return true;
}
signed main(){
	ll n;
	cin >> n;
	if(n == 3){
		cout << "empty";
		return 0;
	}
	for(ll i = 3;i <= n - 2;i += 2){
		if(check(i,i + 2)) cout << i << " " << i + 2 << endl;
	}
	if(empty) cout << "empty";
}

-1

heijie LV 8 @ 2022-1-11 10:23:19

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int sum = 0;
    for(int i = 3; i + 2 <= n ; i +=2)
    {
    	int flag =1;
    	for(int j = 2; j*j <= i;j++)
    	{
    		if(i%j == 0)
    		{
    			flag = 0;
    			break;
			}
		}
		if (flag == 0)
			continue;
		for(int j = 2 ; j*j<=i+2; j++)
		{
			if((i+2)%j == 0)
			{
				flag = 0;
				break;
			}
		}
		if(flag == 1)
		{
			sum++;
			cout << i << " " << i + 2 << endl;
		}
	}
if(sum == 0)
{
	cout <<"empty\n";
}
	return 0;
}

-2

zxc2022 LV 7 @ 2023-3-31 21:19:58

#include<bits/stdc++.h> using namespace std; bool f(int n) { if(n<=1) return 0; for(int i=2;i<=sqrt(n);i++) if(n%i0) return false; return true; } int main() { int n,s=0; cin>>n; for(int i=2;i<=n;i++) { if(f(i)&&f(i+2)&&i+2<=n) { cout<<i<<" "<<i+2<<endl; s=1; } } if(s0) cout<<"empty"; return 0; }

-2

2022ts024 LV 7 @ 2023-2-4 22:12:49

其实这题很简单，只需要埃氏筛法就行，不知为啥各位大老搞这么复杂？ #include <bits/stdc++.h> using namespace std;

bool flag[10005]; void isPrime() { memset(flag, true, sizeof(flag)); flag[0] = flag[1] = false; for (int i = 2; i <= 10000; i++) { if (flag[i]) { for (int j = 2; j <= 10000 / i; j++) { flag[i * j] = false; } } } }

int main() { isPrime(); int x, y; cin >> x >> y; bool vis = false; for (int i = x; i <= y; i++) { if (flag[i] && flag[i+2]) { cout << i << " " << i + 2 << endl; vis = true; } } if (!vis) cout << "empty" << endl; return 0; }

-2

戴思李 LV 6 @ 2022-10-2 22:03:35

#include #include <math.h> #include #include <stdio.h> #include #include #include #include <string.h> #include using namespace std; #define LL long long const int N = 1e6 + 10; const int INF = 0x3f3f3f3f; int a[N],sum[N]; bool pd(int a) { for(int i=2;i<a;i++) { if(a%i0) { return false; } } return true; } int main() { int n,h=0; cin>>n; for(int i=2;i<n;i++) { if(pd(i)&&pd(i+2)) { cout<<i<<' '<<i+2<<endl; h=1; } } if(h0) { cout<<"empty"; } }

-2

孙洋1 LV 9 @ 2022-3-8 17:07:02

#include #include<bits/stdc++.h> using namespace std; bool ss(int x){ for(int i=2;i<x/2;i++){ if(x%i==0) return false; } return true; } int main(){ int n,i,j; bool a=true; cin>>n; for(i=3;i<=n;i+=2){ if(ss(i)&&ss(i+2)&&i+2<=n){ cout<<i<<" "<<i+2<<endl; a=false; } } if(a) cout<<"empty"; return 0; }

-2

limingjie LV 7 @ 2022-1-11 10:07:30

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int sum = 0;
    for(int i = 3; i + 2 <= n ; i +=2)
    {
    	int flag =1;
    	for(int j = 2; j*j <= i;j++)
    	{
    		if(i%j == 0)
    		{
    			flag = 0;
    			break;
			}
		}
		if (flag == 0)
			continue;
		for(int j = 2 ; j*j<=i+2; j++)
		{
			if((i+2)%j == 0)
			{
				flag = 0;
				break;
			}
		}
		if(flag == 1)
		{
			sum++;
			cout << i << " " << i + 2 << endl;
		}
	}
if(sum == 0)
{
	cout <<"empty\n";
}
	return 0;
}

-4

wangyihan LV 7 @ 2022-1-11 10:23:31

#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
int main()
{
    int n;
    cin >> n;
    int sum = 0;
    for(int i = 3 ; i + 2 <= n ; i += 2)
    {
        int flag = 1;
        for(int j = 2; j*j <= i ; j++)
        {
            if(i%j == 0)
            {
                flag = 0;
                break;
            }
        }
        if(flag == 0)
        {
            sum++;
            cout << i << " " << i + 2 << endl;
        }
    }
    if(sum==0)
    {
        cout << "empty\n";
    }
    return 0;
}```

17 条题解

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17 条题解

素数对

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