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  1. using System;
  2. using System.Text;
  3. using System.Collections.Generic;
  4. using System.Diagnostics;
  5.  
  6. public class Test
  7. {
  8.     public static void Main()
  9.     {
  10.         string Text = GetText(50000);
  11.         List<int> Indexes = GetIndexes(2000, Text.Length);
  12.  
  13.         Stopwatch clean1 = new Stopwatch();
  14.         clean1.Start();
  15.         string clean1Result = null;
  16.         for (int i = 0; i < 100; i++)
  17.         {
  18.             clean1Result = Clean1(Text, Indexes);
  19.         }
  20.         clean1.Stop();
  21.  
  22.         Stopwatch clean2 = new Stopwatch();
  23.         clean2.Start();
  24.         string clean2Result = null;
  25.         for (int i = 0; i < 100; i++)
  26.         {
  27.             clean2Result = Clean2(Text, Indexes);
  28.         }
  29.         clean2.Stop();
  30.  
  31.         Stopwatch clean3 = new Stopwatch();
  32.         clean3.Start();
  33.         string clean3Result = null;
  34.         for (int i = 0; i < 100; i++)
  35.         {
  36.             clean3Result = Clean3(Text, Indexes);
  37.         }
  38.         clean3.Stop();
  39.  
  40.         Console.WriteLine("Clean 1: {0}", clean1.ElapsedMilliseconds);
  41.         Console.WriteLine("Clean 2: {0}", clean2.ElapsedMilliseconds);
  42.         Console.WriteLine("Clean 3: {0}", clean3.ElapsedMilliseconds);
  43.     }
  44.  
  45.     public static string GetText(int length)
  46.     {
  47.         var random = new Random();
  48.         StringBuilder sb = new StringBuilder(length);
  49.         for (int i = 0; i < length; i++)
  50.         {
  51.             sb.Append(random.Next(0, 10));
  52.         }
  53.         return sb.ToString();
  54.     }
  55.  
  56.     public static List<int> GetIndexes(int length, int textLength)
  57.     {
  58.         var random = new Random();
  59.         var list = new List<int>(length);
  60.         int max = (int)(textLength * 1.5);
  61.         for (int i = 0; i < length; i++)
  62.         {
  63.             list.Add(random.Next(0, max));
  64.         }
  65.         return list;
  66.     }
  67.  
  68.     public static string Clean1(string Text, List<int> Indexes)
  69.     {
  70.         HashSet<int> hashSet = new HashSet<int>(Indexes);
  71.         StringBuilder sb = new StringBuilder(Text.Length);
  72.         for (int i = 0; i < Text.Length; ++i)
  73.         {
  74.             if (!hashSet.Contains(i))
  75.             {
  76.                 sb.Append(Text[i]);
  77.             }
  78.         }
  79.         return sb.ToString();
  80.     }
  81.  
  82.     public static string Clean2(string Text, List<int> Indexes)
  83.     {
  84.         const char temp = '\uFFF0';
  85.         StringBuilder sb = new StringBuilder(Text);
  86.         for (int i = 0; i < Indexes.Count; i++)
  87.         {
  88.             if (Indexes[i] < sb.Length)
  89.             {
  90.                 sb[Indexes[i]] = temp;
  91.             }
  92.         }
  93.         return sb.Replace(temp.ToString(), null).ToString();
  94.     }
  95.  
  96.     public static string Clean3(string Text, List<int> Indexes)
  97.     {
  98.         bool[] exclude = new bool[Text.Length];
  99.         for (int i = 0; i < Indexes.Count; i++)
  100.         {
  101.             if (Indexes[i] < exclude.Length)
  102.             {
  103.                 exclude[Indexes[i]] = true;
  104.             }
  105.         }
  106.         StringBuilder sb = new StringBuilder(Text.Length);
  107.         for (int i = 0; i < Text.Length; i++)
  108.         {
  109.             if (!exclude[i])
  110.             {
  111.                 sb.Append(Text[i]);
  112.             }
  113.         }
  114.         return sb.ToString();
  115.     }
  116. }
Success #stdin #stdout 0.6s 24088KB
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stdin
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Standard input is empty
stdout
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Clean 1: 335
Clean 2: 84
Clean 3: 125
https://ideone.com/3d2uPH
language:
C# (gmcs 5.20.1)
created:
8 years ago
visibility:
public

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