import sys

nums = map(int, sys.stdin.read().split())
length = nums.pop(0)

result = sum_value = sum(nums)


def calc(deep, total=0, ignore=[]):
    global result
    for i in range(length):
        if i in ignore:
            continue
        t = total + nums[i]
        if deep > 0:
            ignore.append(i)
            calc(deep - 1, t, ignore)
        else:
            diff = abs(sum_value - t * 2)
            if result > diff:
                result = diff
                if result == 0:
                    break


for i in range(length / 2):
    calc(i)
    if result == 0:
        break

print result

Try to use itertools or just bitmasks.
(I can't understand your code.  I got my AC just iterating through all numbers 1...2^N-1)