组合

  static void Main(string[] args)
        {
            List<int> dataList = new List<int>();
            //dataList.Add(3);
            //dataList.Add(3);
            //dataList.Add(2);
            //dataList.Add(5);
            //dataList.Add(1);
            //dataList.Add(4);
            //dataList.Add(2);

            List<List<int>> selectIndex = GetListIndex(dataList);

            foreach (var oneList in selectIndex)
            {
                foreach (var item in oneList)
                {
                    Console.Write(item);
                    Console.Write("  ");
                }
                Console.WriteLine();
            }

            Console.ReadKey();
        }

        static List<List<int>> GetListIndex(List<int> dataList)
        {
            List<List<int>> rtn = new List<List<int>>();

            List<int> initNum = new List<int>();
            foreach (var item in dataList)
            {
                initNum.Add(0);
            }
            //获得所有 数字的集合
            bool isLast = false;
            while (true)
            {
                rtn.Add(initNum);
                initNum = GetNextNum(initNum, dataList, ref isLast);
                if (isLast == true) break;
            }
            return rtn;
        }
        static List<int> GetNextNum(List<int> num, List<int> digitRadix, ref bool isLast)
        {
            List<int> rtn = new List<int>();
            bool isNextAdd = false;
            for (int i = 0; i < num.Count(); i++)
            {
                int thisDigit = num[i];
                if ((i == 0) || (isNextAdd == true))
                {
                    thisDigit++;
                    if (thisDigit >= digitRadix[i])
                    {
                        isNextAdd = true;
                        thisDigit = 0;
                    }
                    else
                    {
                        isNextAdd = false;
                    }
                }
                if ((i == num.Count() - 1) && (isNextAdd == true))
                {
                    isLast = true;
                }
                rtn.Add(thisDigit);
            }

            return rtn;
        }

static void Main(string[] args)
        {
            int count = 3;

            //Stopwatch sw = new Stopwatch();
            //sw.Start();
            //List<List<int>> selectIndex = GetOneListIndex(count);
            //sw.Stop();
            //Console.WriteLine("总运行时间：" + sw.Elapsed);

            Stopwatch sw2 = new Stopwatch();
            sw2.Start();
            List<List<int>> selectIndex2 = GetOneListIndex2(count);
            sw2.Stop();
            Console.WriteLine("总运行时间：" + sw2.Elapsed);

            foreach (var oneList in selectIndex2)
            {
                foreach (var item in oneList)
                {
                    Console.Write(item);
                    Console.Write("  ");
                }
                Console.WriteLine();
            }

            Console.ReadKey();
        }

        static List<List<int>> GetOneListIndex(int digit)
        {
            List<List<int>> rtn = new List<List<int>>();

            //获得位数的字符串“222”
            StringBuilder digitRadix = new StringBuilder();
            StringBuilder initNum = new StringBuilder();
            for (int i = 0; i < digit; i++)
            {
                digitRadix.Append("2");
                initNum.Append("0");
            }
            //获得所有 数字的集合
            List<string> allCollection = new List<string>();
            string num = initNum.ToString();
            while (true)
            {
                num = GetNextNum(num, digitRadix.ToString());
                if (num == initNum.ToString()) break;
                allCollection.Add(num);
            }

            //获得所有的组合
            foreach (var item in allCollection)
            {
                List<int> oneCollection = new List<int>();
                rtn.Add(oneCollection);
                for (int i = 0; i < item.Length; i++)
                {
                    int index = int.Parse(item[i].ToString());
                    if (index == 1)
                    {
                        oneCollection.Add(i);
                    }
                }
            }

            return rtn;
        }
        static string GetNextNum(string num, string digitRadix)
        {
            StringBuilder rtn = new StringBuilder();
            bool isNextAdd = false;
            for (int i = 0; i < num.Count(); i++)
            {
                int thisDigit = int.Parse(num[i].ToString());
                if ((i == 0) || (isNextAdd == true))
                {
                    thisDigit++;
                    int thisRadix = int.Parse(digitRadix[i].ToString());
                    if (thisDigit >= thisRadix)
                    {
                        isNextAdd = true;
                        thisDigit = 0;
                    }
                    else
                    {
                        isNextAdd = false;
                    }
                }
                rtn.Append(thisDigit);
            }

            return rtn.ToString();
        }
        static List<List<int>> GetOneListIndex2(int digit)
        {
            List<List<int>> rtn = new List<List<int>>();

            //获得位数的字符串“222”
            List<int> digitRadix = new List<int>();
            List<int> initNum = new List<int>();
            for (int i = 0; i < digit; i++)
            {
                digitRadix.Add(2);
                initNum.Add(0);
            }
            //获得所有 数字的集合
            List<List<int>> allCollection = new List<List<int>>();
            bool isLast = false;
            while (true)
            {
                initNum = GetNextNum(initNum, digitRadix, ref isLast);
                if (isLast == true) break;
                allCollection.Add(initNum);
            }

            //获得所有的组合
            foreach (List<int> item in allCollection)
            {
                List<int> oneCollection = new List<int>();
                rtn.Add(oneCollection);
                for (int i = 0; i < item.Count; i++)
                {
                    if (item[i] == 1)
                    {
                        oneCollection.Add(i);
                    }
                }
            }

            return rtn;
        }
        static List<int> GetNextNum(List<int> num, List<int> digitRadix, ref bool isLast)
        {
            List<int> rtn = new List<int>();
            bool isNextAdd = false;
            for (int i = 0; i < num.Count(); i++)
            {
                int thisDigit = num[i];
                if ((i == 0) || (isNextAdd == true))
                {
                    thisDigit++;
                    if (thisDigit >= digitRadix[i])
                    {
                        isNextAdd = true;
                        thisDigit = 0;
                    }
                    else
                    {
                        isNextAdd = false;
                    }
                }
                if ((i == num.Count() - 1) && (isNextAdd == true))
                {
                    isLast = true;
                }
                rtn.Add(thisDigit);
            }

            return rtn;
        }