Problem 10: Calculate the sum of all the primes below two million.
I am using: Sieve of Eratosthenes
public class runner {
public static void main(String[] args) {
int num = 2000000;
long sum = 0;
long time = System.currentTimeMillis();
boolean[] arr = new boolean[num+1];
arr[1] = true;//1 doesnt count
for(int i = 2; i<=num;i++){
if(arr[i]){ continue; }
int j=i+i;
while(j