如何用Java递归地从N个元素集中生成所有k个元素子集 [英] How to Generate all k-elements subsets from an N-elements set recursively in Java

问题描述

因此，我陷入了尝试从给定的N个元素集中查找所有k个元素子集的问题。我知道使用公式C（n，k）= C（n-1，k-1）+ C（n-1，k）的k个子集的总数是多少，我也有一个想法以迭代的方式，但是当我尝试考虑递归解决方案时，我陷入了困境。谁能给我一个提示？
谢谢！

So I am stuck with this problem of trying to find all k-elements subsets from a given N-elements set. I know what the total number of k-subsets is using the formula C(n,k)=C(n-1, k-1)+C(n-1, k) and I also have an idea how to do it in a iterative manner, but I get stuck when I try to think of a recursive solution. Can anyone give me a hint? Thanks!

推荐答案

对于集合中的每个元素，采用该元素，然后依次添加到所有（k-1）个子集剩下的N-1个元素集。

For each element of the set, take that element, then add in turn to that all (k-1) subsets of the remaining N-1 element set.

那是一个黑暗而暴风雨的夜晚，机长说……

"It was a dark and stormy night, and the Captain said ..."

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