using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;namespace ConsoleApplication3
{class Program{static int[] rnd;static int N = 0;const int result = 6174;static Random rn = new Random();static StringBuilder output = new StringBuilder();static void Main(string[] args){for (int i = 0; i < 99999; i++){rndArr(4);output.AppendLine("初始数为：" + arrToint(rnd).ToString());output.Append("差值过程数分别为：");if (function(rnd)){output.AppendLine("执行次数为" + N.ToString() + "次");output.AppendLine("");N = 0;}}try{string filepath = "d:/1.txt";FileStream fs = new FileStream(filepath, FileMode.Create);StreamWriter sw = new StreamWriter(fs);sw.Write(output);sw.Close();Console.WriteLine("success!");Console.WriteLine("已经写到" + filepath);}catch { Console.Write("0"); }Console.ReadKey();}/// <summary>/// 迭代求计算次数/// </summary>/// <param name="rTemp">差值循环</param>/// <returns>找到固定值返回True</returns>static bool function(int[] rTemp){cba(rnd); //整理成可转换成最大值的int[]int newint = arrToint(rTemp) - arrTointR(rTemp);N++;output.Append(newint + ",");if (newint == result){return true;}else return function(cba(intToarr(newint)));}/// <summary>/// 数组转换成数值(确保参数为最大值)/// </summary>/// <param name="a"></param>/// <returns>最大值</returns>static int arrToint(int[] a){string temp = "";for (int i = 0; i < a.Length; i++)temp += a[i].ToString();return Int16.Parse(temp);}/// <summary>/// 将数组反向再转换成数值(确保参数为最大值)/// </summary>/// <param name="a"></param>/// <returns>最小值</returns>static int arrTointR(int[] a){string temp = "";for (int i = 0; i < a.Length; i++)temp += a[a.Length - i - 1].ToString();return Int16.Parse(temp);}/// <summary>/// int值转成数组/// </summary>/// <param name="a"></param>/// <returns></returns>static int[] intToarr(int a){int length = a.ToString().Length;int[] re = new int[length];for (int i = 0; i < length; i++){re[i] = a / Convert.ToInt16(Math.Pow(10, length - 1 - i));a = a - re[i] * Convert.ToInt16(Math.Pow(10, length - 1 - i));}return re;}/// <summary>/// 产生初始随机数组/// </summary>/// <param name="length"></param>static void rndArr(int length){rnd = new int[length];int[] rndtemp = new int[rnd.Length];for (int i = 0; i < length; i++){do{rndtemp[i] = rn.Next(10);}while (validate(rndtemp, rndtemp[i], i) || rndtemp[0] == 0);}rnd = rndtemp;}/// <summary>/// Random Validate 如果存在返回true/// </summary>/// <param name="v"></param>/// <param name="x">当前序号标记</param>/// <returns></returns>static bool validate(int[] temp, int v, int x){int k = 0;for (int i = 0; i < x; i++){if (temp[i] == v)k++;}if (k > 0) return true;return false;}/// <summary>/// 随机数组转换成最大值数组/// </summary>/// <param name="temp"></param>/// <returns></returns>static int[] cba(int[] temp){for (int i = 0; i < temp.Length - 1; i++){for (int j = 0; j < temp.Length - i - 1; j++){if (temp[j] < temp[j + 1]){temp[j] = temp[j] + temp[j + 1];temp[j + 1] = temp[j] - temp[j + 1];temp[j] = temp[j] - temp[j + 1];}}}return temp;}}
}

        static void Main(string[] args){Process(1234, 1);Console.ReadKey();}private static void Process(int number, int deep){var numbers = new int[] { number % 10, (number % 100) / 10, (number % 1000) / 100, number / 1000 };var ascOrder = numbers.OrderBy(n => n).ToArray();var descOrder = numbers.OrderByDescending(n => n).ToArray();var weiQuan = 10000;var smaller = ascOrder.Select(a =>{weiQuan = weiQuan / 10;return a * weiQuan;}).Sum();weiQuan = 10000;var bigger = descOrder.Select(a =>{weiQuan = weiQuan / 10;return a * weiQuan;}).Sum();var diff = bigger - smaller;Console.WriteLine(string.Format("第{4}次:{0}:{1}-{2}={3}", number, bigger, smaller, diff, deep));if (diff == number){Console.WriteLine("That's just right");return;}else if (deep >= 10){Console.WriteLine("计算次数超过10次,尚未证明结果,退出");return;}else{Process(diff, ++deep);}}