subset_sum.py

import sys
# Use two blank lines since the methods are defined in
# the global scope. Otherwise use one.


def populate_list(input_lines):
    for input_line in input_lines:
        input_line = int(input_line)
        values_list.append(input_line)


def populate_dict():
    for value in values_list:
        values_dict[value] = True


def value_pair_exists(num):
    for value in values_list:
        if values_dict.get(num - value):
            return True
    return False


# Global variables should be avoided when they could
# potentially be updated by different methods.
# Here it actually saves us the trouble of passing it
# around, therefore makes our code simpler.
values_dict = {}
values_list = []

numbers = sys.argv[1:]
lines = open('data', 'r').read().splitlines()

populate_list(lines)
populate_dict()

for number in numbers:
    number = int(number)
    print value_pair_exists(number)