C# 排列组合取值

来源：互联网发布：网页上编程编辑：程序博客网时间：2024/05/16 04:39
using System;using System.Collections.Generic;using System.Linq;using System.Text;      class Program    {        static void Main(string[] args)        {            //List<string> list = new List<string>();            //for (int i = 0; i < 6; i++)            //{            //    list.Add(i.ToString());            //}            List<string> list = new List<string> { "0", "1", "2", "5", "8", "4", "12", "32" };             Combination.C(list, 3);            Console.WriteLine("---------------------");            //Console.Read();            Combination.A(list, 0, 3);            Console.WriteLine("---------------------");            Console.Read();        }    }    public abstract class Combination    {        public static List<string> GetCombination(List<string> SampleList, int m)        {            if (m == 1)            {                return SampleList;            }            List<string> result = new List<string>();            if (SampleList.Count == m)            {                StringBuilder temp_sb = new StringBuilder();                foreach (string s in SampleList)                {                    temp_sb.Append(s);                }                result.Add(temp_sb.ToString());                Console.WriteLine(temp_sb.ToString());                return result;            }            string temp_firstelement = SampleList[0];            SampleList.RemoveAt(0);            List<string> temp_samplist1 = new List<string>();            temp_samplist1.AddRange(SampleList);            List<string> temp_list1 = GetCombination(temp_samplist1, m - 1);            foreach (string s in temp_list1)            {                result.Add(temp_firstelement + s);                Console.WriteLine(temp_firstelement + s);            }                    List<string> temp_samplist2 = new List<string>();            temp_samplist2.AddRange(SampleList);            List<string> temp_list2 = GetCombination(temp_samplist2, m);            result.AddRange(temp_list2);                        return result;        }        /// <summary>        /// 对数组进行组合操作，选取selectCount个元素进行组合        /// </summary>        /// <param name="lsArray">即将进行组合操作的数组</param>        /// <param name="selectCount">选取的元素的个数</param>        public static void C(List<string> lsArray, int selectCount)        {            int totolcount = lsArray.Count;            int[] currectselect = new int[selectCount];            int last = selectCount - 1;            for (int i = 0; i < selectCount; i++)            {                currectselect[i] = i;            }            while (true)            {                for (int i = 0; i < selectCount; i++)                {                    Console.Write(" {0} ", lsArray[currectselect[i]]);                }                Console.WriteLine();                if (currectselect[last] < totolcount - 1)                {                    currectselect[last]++;                }                else                {                    int pos = last;                    while (pos > 0 && currectselect[pos - 1] == currectselect[pos] - 1)                    {                        pos--;                    }                    if (pos == 0) return;                    currectselect[pos - 1]++;                    for (int i = pos; i < selectCount; i++)                    {                        currectselect[i] = currectselect[i - 1] + 1;                    }                }            }        }        /// <summary>        /// 对数组进行全排列        /// </summary>        /// <param name="lsArray">要进行全排列的数组</param>        /// <param name="begin">进行全排列的开始下标</param>        /// <param name="end">进行全排列的结束下标</param>       public static void A(List<string> lsArray, int begin, int end)        {            if (begin == end)            {                for (int i = 0; i <= end; i++)                   Console.Write(" {0} ", lsArray[i]);                Console.WriteLine();            }            for (int i = begin; i <= end; i++)            {                Swap(lsArray, begin, i);                A(lsArray, begin + 1, end);                Swap(lsArray, begin, i);            }        }         /// <summary>        /// 交换数组中的下标为x,y的值        /// </summary>        /// <param name="lsArray">该数组</param>        /// <param name="x"></param>        /// <param name="y"></param>        static void Swap(List<string> lsArray, int x, int y)        {            string t = lsArray[x];            lsArray[x] = lsArray[y];            lsArray[y] = t;        }    }
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