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  1. using System;
  2. using System.Text;
  3.  
  4. namespace ConsoleApplication51
  5. {
  6.     class Program
  7.     {
  8.         static class RangeChecker
  9.         {
  10.             public static string BuildRegex(string matches)
  11.             {
  12.                 string[] splits = matches.Split(',');
  13.  
  14.                 if (splits.Length == 0)
  15.                 {
  16.                     return "^()$";
  17.                 }
  18.  
  19.                 StringBuilder res = new StringBuilder();
  20.                 res.Append("^(");
  21.  
  22.                 foreach (string split in splits)
  23.                 {
  24.                     if (split == "*")
  25.                     {
  26.                         return "^([0-9]+)$";
  27.                     }
  28.  
  29.                     string[] subSplit = split.Split('-');
  30.  
  31.                     string min = subSplit[0].TrimStart('0');
  32.  
  33.                     if (min == string.Empty)
  34.                     {
  35.                         return null;
  36.                     }
  37.  
  38.                     if (subSplit.Length == 1)
  39.                     {
  40.                         res.Append(min);
  41.                         res.Append('|');
  42.  
  43.                         continue;
  44.                     }
  45.                     else if (subSplit.Length > 2)
  46.                     {
  47.                         return null;
  48.                     }
  49.  
  50.                     string max = subSplit[1].TrimStart('0');
  51.  
  52.                     if (max == string.Empty)
  53.                     {
  54.                         return null;
  55.                     }
  56.  
  57.                     if (min.Length > max.Length)
  58.                     {
  59.                         return null;
  60.                     }
  61.  
  62.                     // For 2-998 we first produce 2-9, then 10-99
  63.                     string tempMin = BuildRegexDifferentLength(res, min, max);
  64.  
  65.                     if (tempMin == null)
  66.                     {
  67.                         return null;
  68.                     }
  69.  
  70.                     // Then here 100-998
  71.                     BuildRegexSameLength(res, tempMin, max);
  72.                 }
  73.  
  74.                 res.Length--;
  75.                 res.Append(")$");
  76.  
  77.                 return res.ToString();
  78.             }
  79.  
  80.             private static bool IsOnlyDigit(string str, int start, char digit)
  81.             {
  82.                 for (int i = start; i < str.Length; i++)
  83.                 {
  84.                     if (str[i] != digit)
  85.                     {
  86.                         return false;
  87.                     }
  88.                 }
  89.  
  90.                 return true;
  91.             }
  92.  
  93.             private static string BuildRangeDigit(char min, char max)
  94.             {
  95.                 if (min == max)
  96.                 {
  97.                     return min.ToString();
  98.                 }
  99.  
  100.                 return "[" + min + "-" + max + "]";
  101.             }
  102.  
  103.             private static string BuildRegexDifferentLength(StringBuilder res, string min, string max)
  104.             {
  105.                 string tempMin = min;
  106.  
  107.                 for (int i = min.Length; i < max.Length; i++)
  108.                 {
  109.                     string tempMax = new string('9', i);
  110.  
  111.                     BuildRegexSameLength(res, tempMin, tempMax);
  112.  
  113.                     tempMin = "1" + new string('0', i);
  114.                 }
  115.  
  116.                 if (tempMin.CompareTo(max) > 0)
  117.                 {
  118.                     return null;
  119.                 }
  120.  
  121.                 return tempMin;
  122.             }
  123.  
  124.             private static void BuildRegexSameLength(StringBuilder res, string min, string max)
  125.             {
  126.                 // 100-100
  127.                 if (min == max)
  128.                 {
  129.                     res.Append(min);
  130.                     res.Append('|');
  131.  
  132.                     return;
  133.                 }
  134.  
  135.                 int commonPart = 0;
  136.  
  137.                 for (; commonPart < min.Length; commonPart++)
  138.                 {
  139.                     if (min[commonPart] != max[commonPart])
  140.                     {
  141.                         break;
  142.                     }
  143.                 }
  144.  
  145.                 RecursivelyAddRegexRange(res, min.Substring(0, commonPart), min.Substring(commonPart), max.Substring(commonPart));
  146.             }
  147.  
  148.             private static void RecursivelyAddRegexRange(StringBuilder res, string prefix, string min, string max)
  149.             {
  150.                 if (min.Length == 1)
  151.                 {
  152.                     res.Append(prefix);
  153.                     res.Append(BuildRangeDigit(min[0], max[0]));
  154.                     res.Append('|');
  155.  
  156.                     return;
  157.                 }
  158.  
  159.                 // Check if 
  160.                 bool only0Min = IsOnlyDigit(min, 1, '0');
  161.                 bool only9Max = IsOnlyDigit(max, 1, '9');
  162.  
  163.                 if (only0Min && only9Max)
  164.                 {
  165.                     res.Append(prefix);
  166.                     res.Append(BuildRangeDigit(min[0], max[0]));
  167.  
  168.                     for (int i = 1; i < min.Length; i++)
  169.                     {
  170.                         res.Append("[0-9]");
  171.                     }
  172.  
  173.                     res.Append('|');
  174.  
  175.                     return;
  176.                 }
  177.  
  178.                 string middleMin = min;
  179.  
  180.                 if (!only0Min)
  181.                 {
  182.                     RecursivelyAddRegexRange(res, prefix + min[0], min.Substring(1), new string('9', min.Length - 1));
  183.  
  184.                     if (min[0] != '9')
  185.                     {
  186.                         middleMin = (char)(min[0] + 1) + new string('0', min.Length - 1);
  187.                     }
  188.                     else
  189.                     {
  190.                         middleMin = null;
  191.                     }
  192.                 }
  193.  
  194.                 string middleMax = max;
  195.  
  196.                 if (!only9Max)
  197.                 {
  198.                     if (max[0] != '0')
  199.                     {
  200.                         middleMax = (char)(max[0] - 1) + new string('9', max.Length - 1);
  201.                     }
  202.                     else
  203.                     {
  204.                         middleMax = null;
  205.                     }
  206.                 }
  207.  
  208.                 if (middleMin != null && middleMax != null && middleMin[0] <= middleMax[0])
  209.                 {
  210.                     RecursivelyAddRegexRange(res, prefix + BuildRangeDigit(middleMin[0], middleMax[0]), middleMin.Substring(1), middleMax.Substring(1));
  211.                 }
  212.  
  213.                 if (!only9Max)
  214.                 {
  215.                     RecursivelyAddRegexRange(res, prefix + max[0], new string('0', max.Length - 1), max.Substring(1));
  216.                 }
  217.             }
  218.         }
  219.  
  220.         static void Main(string[] args)
  221.         {
  222.             Action<string> printRegex = p => Console.WriteLine("{0}: {1}", p, RangeChecker.BuildRegex(p));
  223.  
  224.             printRegex("*");
  225.             printRegex("1");
  226.             printRegex("1,*");
  227.             printRegex("1,2,3,4");
  228.             printRegex("1,11-88");
  229.             printRegex("1,11-88,90-101");
  230.             printRegex("1-11111");
  231.             printRegex("75-11119");
  232.         }
  233.     }
  234. }
  235.  
Success #stdin #stdout 0.06s 34192KB
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stdin
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Standard input is empty
stdout
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*: ^([0-9]+)$
1: ^(1)$
1,*: ^([0-9]+)$
1,2,3,4: ^(1|2|3|4)$
1,11-88: ^(1|1[1-9]|[2-7][0-9]|8[0-8])$
1,11-88,90-101: ^(1|1[1-9]|[2-7][0-9]|8[0-8]|9[0-9]|10[0-1])$
1-11111: ^([1-9]|[1-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|10[0-9][0-9][0-9]|110[0-9][0-9]|1110[0-9]|1111[0-1])$
75-11119: ^(7[5-9]|[8-9][0-9]|[1-9][0-9][0-9]|[1-9][0-9][0-9][0-9]|10[0-9][0-9][0-9]|110[0-9][0-9]|111[0-1][0-9])$
https://ideone.com/3aEt3E
language:
C# (gmcs 5.20.1)
created:
12 years ago
visibility:
public

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