排列数据的输出

 排列组合是高中是学到的 知识，理论上很清楚，但如何使用代码实现，却一直没有尝试过，近段时间由于项目需要，写一个排列的算法，想不到却花费了不少时间。

   需求很简单，就是典型的排列应用。

例如输入：C0,C1,C2,C3,C4,输出C0,C1,C2,C3,C4的所有排列。

实现代码：

  /// <summary>        /// 输出所有排列的数据        /// </summary>        /// <param name="columns">输入的排列的所有元素</param>        /// <param name="columnsContain">输出元素列表，已添加的元素</param>        /// <param name="key"></param>        /// <returns></returns>        private static string CreateAllSequenceData(List<string> columns, List<string> columnsContain, string key)        {            StringBuilder strs = new StringBuilder();            List<string> columnsContaininer = new List<string>();            bool hasAddParentcolumns = false;//是否已添加上层循环传入的元素            for (int i = 0; i < columns.Count; i++)            {                string item = columns[i];                if (!hasAddParentcolumns)                {                    columnsContaininer.AddRange(columnsContain);                    hasAddParentcolumns = true;                }                if (columnsContaininer.Count == columns.Count)//所有元素已添加，输出排列                {                    string value = GetSequenceKey(columnsContaininer);                    strs.AppendLine(key + ":" + value);                    break;                }                if (!columnsContaininer.Contains(item))//当前元素还没有添加到输出元素列表中                {                    columnsContaininer.Add(item);                    if (columnsContaininer.Count == columns.Count)//所有元素已添加，输出排列                    {                        string value = GetSequenceKey(columnsContaininer);                        strs.AppendLine(key + ":" + value);                        break;                    }                    else//还有元素没有添加，递归调用                    {                        strs.Append(CreateAllSequenceData(columns, columnsContaininer, key));                    }                    columnsContaininer.Clear();//情况内部循环递归调用添加的元素                    hasAddParentcolumns = false;                }            }            return strs.ToString();        }        private static string GetSequenceKey(List<string> columns)        {            StringBuilder strs = new StringBuilder();            for (int i = 0; i < columns.Count; i++)            {                strs.Append(columns[i] + "_");            }            return strs.ToString();        }        //生成所有排列        public static string CreateAllGroupingData(List<string> columns)        {                      StringBuilder strs = new StringBuilder();                       string key = GetSequenceKey(columns);            List<string> columnsContain = new List<string>();            strs.Append(CreateAllSequenceData(columns, columnsContain, key));            return strs.ToString();        }        /// <summary>        /// 测试代码        /// </summary>        public static void Test()        {            List<string> columns = new List<string>();            columns.Add("c0");            columns.Add("c1");            columns.Add("c2");            columns.Add("c3");            string text = CreateAllGroupingData(columns);            WrieData(text);                }        private static void WrieData(string text)        {            string file = "ZuheTestout.js";            StreamWriter sr = new StreamWriter(file);            sr.WriteLine(text);            sr.Close();        }

第二种算法：

 private static string CreateAllSequenceData2(List<string> columns, List<string> columnsContain, string key,int maxlength)        {            StringBuilder strs = new StringBuilder();            List<string> columnsContaininer = new List<string>();            List<string> InnerColumns = GetInnerColumns(columns, columnsContain);            bool hasAddParentcolumns = false;//是否已添加上层循环传入的元素            for (int i = 0; i < InnerColumns.Count; i++)            {                string item = InnerColumns[i];                if (!hasAddParentcolumns)                {                    columnsContaininer.AddRange(columnsContain);                    hasAddParentcolumns = true;                }                                       columnsContaininer.Add(item);                    if (columnsContaininer.Count == maxlength)//所有元素已添加，输出排列                    {                        string value = GetSequenceKey(columnsContaininer);                        strs.AppendLine(key + ":" + value);                        return strs.ToString();                    }                    else//还有元素没有添加，递归调用                    {                        strs.Append(CreateAllSequenceData2(InnerColumns, columnsContaininer, key, maxlength));                        columnsContaininer.Clear();//情况内部循环递归调用添加的元素                        hasAddParentcolumns = false;                        }                               }            return strs.ToString();        }        private static List<string> GetInnerColumns(List<string> columnsAll, List<string> columnsContain)        {            List<string> InnerColumns = new List<string>();            for (int i = 0; i < columnsAll.Count;i++ )            {                string item = columnsAll[i];                if (!columnsContain.Contains(item)) {                    InnerColumns.Add(item);                }            }            return InnerColumns;        }        //生成所有组合        public static string CreateAllGroupingData(List<string> columns)        {                      StringBuilder strs = new StringBuilder();                       string key = GetSequenceKey(columns);            List<string> columnsContain = new List<string>();            strs.Append(CreateAllSequenceData2(columns, columnsContain, key, columns.Count));          //  strs.Append(CreateAllSequenceData2(columns, columnsContain, key, columns.Count, 0, ""));            return strs.ToString();        }

第三种

 private static string CreateAllSequenceData3(List<string> columns, List<string> columnsContain, string key, int maxlength,int columnsContainlength,  string parentcolumn)        {            StringBuilder strs = new StringBuilder();            List<string> columnsContaininer = new List<string>();            columnsContaininer.AddRange(columnsContain);            columnsContaininer.Add(parentcolumn);            List<string> InnerColumns = GetInnerColumns(columns, columnsContaininer);                   for (int i = 0; i < InnerColumns.Count; i++)            {                string item = InnerColumns[i];                if (columnsContainlength + 1 == maxlength)//所有元素已添加，输出排列                {                    columnsContaininer.Add(item);                    string value = GetSequenceKey(columnsContaininer);                    strs.AppendLine(key + ":" + value);                    return strs.ToString();                }                else//还有元素没有添加，递归调用                {                    strs.Append(CreateAllSequenceData3(InnerColumns, columnsContaininer, key, maxlength, columnsContainlength + 1, item));                                 }            }            return strs.ToString();        }        //生成所有组合        public static string CreateAllGroupingData(List<string> columns)        {            StringBuilder strs = new StringBuilder();            string key = GetSequenceKey(columns);            List<string> columnsContain = new List<string>();            //  strs.Append(CreateAllSequenceData2(columns, columnsContain, key, columns.Count));            strs.Append(CreateAllSequenceData3(columns, columnsContain, key, columns.Count, 0, ""));            return strs.ToString();        }