0003.py

def isprime(n):
    i = 2
    while i < n:
        if n % i == 0:
            return False
        i += 1
    return True

def genprimefactors(n):
    i = 2
    while i < n:
        if n % i == 0:
            if isprime(i):
                yield i
        i += 1

def test():
    """test isprime"""
    if not isprime(3) or isprime(4) or not isprime(29) or isprime(30):
        raise Exception('isprime broken')
    # this is not a particularily exhaustive test

    """test genprimefactors"""
    primefactors = [i for i in genprimefactors(13195)]
    if [5, 7, 13, 29] != primefactors:
        print primefactors
        raise Exception('genprimefactors did not work')

#    print 'All tests passed'

#    largestprime = 1
#    for i in genprimefactors(600851475143):
#        print i
#        largestprime = i
#    print largestprime

def fn0():
    number = 600851475143
    divisor = 2;
    while (number > 1):
        if (0 == (number % divisor)):
            number /= divisor
        else:
            divisor += 1
    return divisor
        
solutions = [fn0]