根据您的解决方案:
def subsetsum(array,num):
if num == 0 or num < 1:
return None
elif len(array) == 0:
return None
else:
if array[0] == num:
return [array[0]]
else:
with_v = subsetsum(array[1:],(num - array[0]))
if with_v:
return [array[0]] + with_v
else:
return subsetsum(array[1:],num)