Answers for "c++ sieve of eratosthenes"

6

prime of sieve

//sieve of eratosthenes or prime of sieve
#include<iostream>
#include<math.h>
using namespace std;
void primeofsieve(long long int n)
{
	long long int arr[n]={};
	for(int i=2;i<=sqrt(n);i++)
	{
		for(long long int j=i*i;j<=n;j+=i)
			arr[j]=1;
	}
	for(long long int i=2;i<=n;i++)
	{
	    if(arr[i]==0)
	    	cout<<i<<" ";
	}


}
int main()
{

	#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
    #endif
	long long int n;
	cin>>n;
	cout<<"PRIME NUMBERs ARE : ";
	primeofsieve(n);
	return 0;
}
Posted by: Guest on May-27-2020
0

sieve of eratosthenes c++

int n;
vector<bool> is_prime(n+1, true);
is_prime[0] = is_prime[1] = false;
for (int i = 2; i <= n; i++) {
    if (is_prime[i] && (long long)i * i <= n) {
        for (int j = i * i; j <= n; j += i)
            is_prime[j] = false;
    }
}
Posted by: Guest on November-09-2020

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