词组合,而无需重复 [英] Words combinations without repetition
本文介绍了词组合,而无需重复的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有10个字。我怎样才能获得的5个字所有可能的组合(N = 10,K = 5)
。该订单的不要紧。
I have 10 words. How can I get all possible combinations of 5 words (n=10, k=5)
. The order does not matter.
例如:A,B,C,如果k = 2(N =在这种情况下,3)
,它想AB,BC和AC。也许你知道一些有用的代码或例子。
For example: "A", "B", "C", if k=2 (n=3 in this case)
, it would like AB, BC and AC. Maybe you know some usefull code or example.
P.S。很抱歉,如果我没有足够的权利,因为我不知道英语非常好。
P.S. Sorry if I'm not right enough cause I don't know English very good.
推荐答案
你所试图做的是得到一个集合中的所有排列。
What you are trying to do is get all the permutations of a collection.
- Unique permutations of list
- permutations of k objects from a set of n algorithm
以下是代码片段:
static void Main(string[] args)
{
var list = new List<string> { "a", "b", "c", "d", "e" };
var result = GetPermutations(list, 3);
foreach (var perm in result)
{
foreach (var c in perm)
{
Console.Write(c + " ");
}
Console.WriteLine();
}
Console.ReadKey();
}
static IEnumerable<IEnumerable<T>> GetPermutations<T>(IEnumerable<T> items, int count)
{
int i = 0;
foreach (var item in items)
{
if (count == 1)
yield return new T[] { item };
else
{
foreach (var result in GetPermutations(items.Skip(i + 1), count - 1))
yield return new T[] { item }.Concat(result);
}
++i;
}
}
输出:
Outputs:
a b c
a b d
a b e
a c d
a c e
a d e
b c d
b c e
b d e
c d e
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