CodeEval Happy Numbers

happy_numbers.py

import sys


def is_happy_number(n, mem=None):

    if mem is None:
        mem = []

    candidate = sum([int(i) ** 2 for i in n])

    if candidate == 1:
        return 1
    elif candidate in mem:
        return 0
    else:
        mem.append(candidate)
        return is_happy_number(str(candidate), mem)


if __name__ == '__main__':
    test_cases = open(sys.argv[1], 'r')
    for line in test_cases:
        print is_happy_number(line.strip())

    test_cases.close()