由网友(梦浅易醒)分享简介:我正在学习Python和我有一个问题,这个看似简单的任务。I'm learning Python and I have a problem with this seems to be simple task.欲查找相加为一个给定数目的数字的所有可能的组合。 例如:4 - > [1,1,1,1] [1,1,2]...
我正在学习Python和我有一个问题,这个看似简单的任务。
I'm learning Python and I have a problem with this seems to be simple task.
欲查找相加为一个给定数目的数字的所有可能的组合。 例如:4 - > [1,1,1,1] [1,1,2] [2,2] [1,3]
I want to find all possible combination of numbers that sum up to a given number. for example: 4 -> [1,1,1,1] [1,1,2] [2,2] [1,3]
我挑选哪些生成所有可能子集(2 ^ n)和然后将溶液收率只是那些总和等于数。我的条件的问题。 code:
I pick the solution which generate all possible subsets (2^n) and then yield just those that sum is equal to the number. I have a problem with the condition. Code:
def allSum(number):
#mask = [0] * number
for i in xrange(2**number):
subSet = []
for j in xrange(number):
#if :
subSet.append(j)
if sum(subSet) == number:
yield subSet
for i in allSum(4):
print i
BTW是一个不错的方法?
BTW is it a good approach?
推荐答案
下面是一些code我看到了几年前做的伎俩:
Here's some code I saw a few years ago that does the trick:
>>> def partitions(n):
if n:
for subpart in partitions(n-1):
yield [1] + subpart
if subpart and (len(subpart) < 2 or subpart[1] > subpart[0]):
yield [subpart[0] + 1] + subpart[1:]
else:
yield []
>>> print list(partitions(4))
[[1, 1, 1, 1], [1, 1, 2], [2, 2], [1, 3], [4]]
其他参考:
http://mathworld.wolfram.com/Partition.html http://en.wikipedia.org/wiki/Partition_(number_theory ) http://www.site.uottawa.ca/~伊万/ F49-INT-part.pdf http://mathworld.wolfram.com/Partition.html http://en.wikipedia.org/wiki/Partition_(number_theory) http://www.site.uottawa.ca/~ivan/F49-int-part.pdf相关推荐
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