gistfile1.scala

package proj_euler

/*
 * The prime factors of 13195 are 5, 7, 13 and 29.
 * What is the largest prime factor of the number 600851475143 ?
 */

object Problem3 {

	def solve3(num1  : Long) : Long = {
	    var num3 = 2	
	    var num2 = num1 / num3
	    while ((num2 > 2) == true)
	    {
		if ((num1 % num2 == 0) )
		{
	   	    var check_prime = is_prime(num2)
		    if (check_prime == true)
		        return num2
		    else
		    {
			num2 = num2 - 1 
		    }
		}
		else 
		{
		    num3 = num3 + 1 
		    num2 = num1 / num3
		}
	    }
	    return num2
	}

	def is_prime(n: BigInt) : Boolean ={
	    var c = n / 2
	    var d : BigInt = 2
	    while (d < c == true){
	        if (n % d == 0)
		    return false
		else
		    d = d + 1
             }
	     return true
	}
}