算法计算发电机组 [英] Algorithm for calculating the power set

问题描述

我刚刚发现了一个算法寻找发电机组。我用Google搜索的解决方案后，却发现没有一个工作什么好，所以我想通了一个自己。但我不知道它的算法是，因为我无法找到它在网络上或任何书籍。我的意思是，它有名字吗？我几乎觉得我是它的发明者。但比起我发现在一些网站计算发电机组的算法，我觉得我的是更好的，不知道为什么没有人使用它？

I just discovered an algorithm for finding the power set. I googled after solutions, but found none that worked any good, so I figured out one myself. But I wonder what algorithm it is, because I cannot find it on the net or in any books. I mean, does it have a name? I hardly think I'm the inventor of it. But compared to the algorithms I found on some sites for calculating the power set, I think mine is far better and wonder why no one uses it?

这是算法：

R <- []
L <- [ e1, e2 ... en ]
c <- 0
function: powerSet(L, c)
  R <- R union L
  for e in L starting at c
    powerSet(L\{e}, c)
  end
  return R
end

在这里，它是用Java实现的：

And here it is implemented in Java:

public static void powerSet(List<String> list, int count)
{
  result.add(list);

  for(int i = count; i < list.size(); i++)
  {
    List<String> temp = new ArrayList<String>(list);
    temp.remove(i);

    powerSet(temp, i);
  }
}

有没有人认识它，还是我的发明？

Does anyone recognize it, or am I the inventor?

推荐答案

主要有两个原因：

1. 在它使用的全球变量;
2. 这是递归的，虽然这其实并不重要太多，因为它是一个 O（2 ^ n）的算法。

1. It uses global variables;
2. It is recursive, although this doesn't really matter much because it's an O(2^n) algorithm.

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