combinations sum problem

combinations-sum.py

#!/usr/bin/env python

from __future__ import print_function
from itertools import combinations
import sys


def combinations_sum_range(lower, upper, numbers):
    for size in range(len(numbers)):
        for combo in set(combinations(numbers, size + 1)):
            if lower <= sum(combo) <= upper:
                yield combo

if __name__ == '__main__':
    try:
        args = list(map(int, sys.argv[1:]))
        lower = args[0]
        upper = args[1]
        numbers = args[2:]
    except (ValueError, IndexError,):
        print('Usage: {0} MIN MAX [NUM]...'.format(sys.argv[0]))
        sys.exit(1)

    for combo in combinations_sum_range(lower, upper, numbers):
        print(' '.join(map(str, combo)))