gistfile1.py

import fileinput
from itertools import permutations, combinations_with_replacement


def challenge(challenge_str):
    the_split = challenge_str.strip().split(' ')
    if len(the_split) < 2:
        print 'Invalid'
        return
    for d in the_split:
        assert d.isdigit()
    challenge_tupple, answer = the_split[:len(the_split)-1], int(the_split[-1])
    for arg_permutation in permutations(challenge_tupple):
        for op_combinations in combinations_with_replacement('+-*/', len(challenge_tupple)-1):
            result = [None]*(len(challenge_tupple)+len(challenge_tupple)-1)
            result[::2] = arg_permutation
            result[1::2] = op_combinations
            if eval(''.join(result)) == answer:
                print ' '.join(result)
                return
    print 'Invalid'

if __name__ == '__main__':
    for line in fileinput.input():
        challenge(line)