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TwinPrime.java
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TwinPrime.java
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package com.company.Main;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.*;
import java.math.*;
public class Main {
static HashSet<Integer> set = new HashSet<>();
static ArrayList<Integer> primes = new ArrayList<>();
static ArrayList<IntergerPair> twinPrime = new ArrayList<>();
public static void main(String[] args) throws IOException{
/** // write your code here
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String s;
SieveOfEratosthenes(20000000);
for (int i=0;i<primes.size();i++)
{
if (set.contains(primes.get(i)+2))
twinPrime.add(new IntergerPair(primes.get(i),primes.get(i)+2));
}
while ((s= br.readLine())!=null)
{
System.out.println("("+twinPrime.get(Integer.parseInt(s)-1).u+", "+twinPrime.get(Integer.parseInt(s)-1).v+")");
}
*/
BigInteger value =new BigInteger("10000000");
System.out.println(factorial(value));
}
public static BigInteger factorial(BigInteger number) {
BigInteger result = BigInteger.valueOf(1);
for (long factor = 2; factor <= number.longValue(); factor++) {
result = result.multiply(BigInteger.valueOf(factor));
}
return result;
}
private static void SieveOfEratosthenes(int n) {
boolean[] prime = new boolean[n+1];
for (int i=0;i<=n;i++)
prime[i] = true;
for (int factor = 2;factor*factor<=n;factor++)
{
if (prime[factor])
for (int i=factor*factor;i<=n;i+=factor)
prime[i] = false;
}
for (int i=2;i<=n;i++)
if (prime[i])
{
set.add(i);
primes.add(i);
}
}
public static class IntergerPair
{
int u;
int v;
IntergerPair(int u, int v)
{
this.u = u;
this.v = v;
}
}
}