Torry 的困惑

是找前n项质数和 而不是说前n项自然数的质数积
里面用了一种新的找质数的方法
https://blog.csdn.net/kevin_nan/article/details/88300966 里面有写新的质数查找方法

public class main{
	public long countPrimes(int n) {
		 long sum = 1;
		 int n2 = 0;
		 boolean[]arr = new boolean [10000000+1];
		 for(int i = 2 ;i < 10000000+1 ;i++) { 
			 int j = 2;
               if(arr[i]!=true)
			 while(j * i < 10000000+1 ) {
				 arr[j * i ] = true;
				 j++;
			 }
		 }
		 for(int i = 2 ;i< 10000000+1 ;i++) {
			 if(arr[i] != true) {
				 sum = (sum*i)%50000;
				 n2 ++ ;
			 }
			 if(n2 >= n)
				 break;
		 }
				 return sum;
	 }
	   public static void main(String[]args) {
		   Main1 m = new Main1 ();
		   Scanner sc = new Scanner (System.in);
			int n = sc.nextInt();
		   System.out.println(m.countPrimes(n));
		   
	   }
	}