求在C#从M个数中取N个的所有组合算法，无重复

Question

如题

Answer 1

http://topic.csdn.net/u/20090217/21/f41ed9f6-f929-451c-a5c9-80d2e408422a.html?56197

Answer 2

以前为了追求效率都是自己模拟栈，现在还是化繁为简，直接用递归了，代码简单
using System;namespace ConsoleApplication4
{
    class Program
    {
        static string[] Items = new string[] { "A", "B", "C", "D", "E" };        static void Main(string[] args)
        {
            int selectCount = 2;
            Select(0, selectCount, string.Empty);
        }        static void Select(int currentIndex, int remain, string currentSelect)
        {
            if (remain == 0)
            {
                Console.WriteLine(currentSelect);
                return;
            }            if (Items.Length - currentIndex < remain)
                return;            Select(currentIndex + 1, remain - 1, currentSelect + Items[currentIndex]);
            Select(currentIndex + 1, remain, currentSelect);
        }
    }
}