package pe37test;
 
/**
 *
 * @author Caleb
 */
public class Main {
 
    static final int clim = 1000000;
    static boolean nums[];
 
    public static void main(String[] args) {
 
        long t1 = System.nanoTime();
        int sum=0;
 
        findPrimes();
 
        long t2 = System.nanoTime();
        System.out.println("Generates primes in: " + ((t2 - t1) * 1e-6) + " milliseconds");
 
        for (int i = 0; i < clim; i++) {
            if (nums[i]) {
                if (truncateCheck(i)) {
                    System.out.println(i);
                    sum += i;
                }
            }
        }
        System.out.println("Sum:"+sum);
        t2 = System.nanoTime();
        System.out.println("Execution time: " + ((t2 - t1) * 1e-6) + " milliseconds");
    }
 
    public static boolean truncateCheck(int number) {
        for (int i = 1; i < String.valueOf(number).length(); i++) {
            if (nums[Integer.parseInt(String.valueOf(number).substring(i))]==false) {
                return false;
            }
            if (nums[Integer.parseInt(String.valueOf(number).substring(0, i))] == false) {
                return false;
            }
        }
        return true;
    }
 
    public static void findPrimes() {
        nums = new boolean[clim + 1];
        for (int i = 2; i <= clim; i++) {
            nums[i] = true;
        }
        for (int i = 2; i * i <= clim; i++) {
            if (nums[i]) {
                for (int j = i; i * j <= clim; j++) {
                    nums[i * j] = false;
                }
            }
        }
    }
}