"""

Name: string_hash -  a string hashing program

Description: Basic string hashing program according to Theory I lecture.

Author: Eugen Sawin <sawine@informatik.uni-freiburg.de>

"""

def main():    

    args = parse_arguments()

    used = set()

    for key in args.values.split():

        print "%s: %i" % (key, double_hash(int(key), used))

def double_hash(k, used):

    j = 0

    code = (h(k) - s(j, k)) % 15

    while code in used:

        j += 1

        code = (h(k) - s(j, k)) % 15

    used.add(code)

    return code

def s(j, k):

    return j * h2(k)

def h(k):

    return k % 15

def h2(k):

    return 1 + (k % 13) 

from argparse import ArgumentParser

def parse_arguments():

    parser = ArgumentParser(description="Returns the hash for given string using the double-hash technique.")

    parser.add_argument("values", help="values")    

    return parser.parse_args()

if __name__ == "__main__":

    main()