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  1. using System;
  2. using System.Collections.Concurrent;
  3. using System.Collections.Generic;
  4. using System.Diagnostics;
  5. using System.Linq;
  6. using System.Text;
  7. using System.Threading;
  8. using System.Threading.Tasks;
  9.  
  10. namespace ConsoleApplication5
  11. {
  12.     class Program
  13.     {
  14.         static long TestForeach()
  15.         {
  16.             var stopWatch = new Stopwatch();
  17.             stopWatch.Start();
  18.  
  19.             var list = new List<int>();
  20.  
  21.             foreach (var i in Enumerable.Range(0, 10000))
  22.             {
  23.                 list.Add(i);
  24.             }
  25.  
  26.             stopWatch.Stop();
  27.             return stopWatch.ElapsedMilliseconds;
  28.         }
  29.  
  30.         static long TestParallelForEach()
  31.         {
  32.             var list = new List<int>();
  33.             var stopWatch = new Stopwatch();
  34.             stopWatch.Start();
  35.             Parallel.ForEach(Enumerable.Range(0, 10000), new ParallelOptions() { MaxDegreeOfParallelism = 1000 }, i =>
  36.             {
  37.                 lock (list)
  38.                 {
  39.                     list.Add(i);
  40.                 }
  41.             });
  42.  
  43.             stopWatch.Stop();
  44.             return stopWatch.ElapsedMilliseconds;
  45.         }
  46.  
  47.         static long TestParallelForEachThreadSafeCollection()
  48.         {
  49.             var list = new BlockingCollection<int>();
  50.             var stopWatch = new Stopwatch();
  51.             stopWatch.Start();
  52.             Parallel.ForEach(Enumerable.Range(0, 10000), new ParallelOptions() { MaxDegreeOfParallelism = 1000 }, i =>
  53.             {
  54.                 list.Add(i);
  55.             });
  56.  
  57.             stopWatch.Stop();
  58.             return stopWatch.ElapsedMilliseconds;
  59.         }
  60.  
  61.         static void Main(string[] args)
  62.         {
  63.             var times = new List<long>();
  64.             Console.WriteLine("■TestForeach");
  65.             Enumerable.Range(0, 1000).ToList().ForEach(i => times.Add(TestForeach()));
  66.             //Enumerable.Range(0, 1000).ToList().ForEach(i => Console.WriteLine(times[i]));
  67.             Console.WriteLine(times.Average());
  68.  
  69.             times = new List<long>();
  70.             Console.WriteLine("■TestParallelForEach");
  71.             Enumerable.Range(0, 1000).ToList().ForEach(i => times.Add(TestParallelForEach()));
  72.             //Enumerable.Range(0, 1000).ToList().ForEach(i => Console.WriteLine(times[i]));
  73.             Console.WriteLine(times.Average());
  74.  
  75.             times = new List<long>();
  76.             Console.WriteLine("■TestParallelForEachThreadSafeCollection");
  77.             Enumerable.Range(0, 1000).ToList().ForEach(i => times.Add(TestParallelForEachThreadSafeCollection()));
  78.             //Enumerable.Range(0, 1000).ToList().ForEach(i => Console.WriteLine(times[i]));
  79.             Console.WriteLine(times.Average());
  80.         }
  81.     }
  82. }
Time limit exceeded #stdin #stdout 5s 34720KB
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Standard input is empty
stdout
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■TestForeach
0.014
■TestParallelForEach
1.448
■TestParallelForEachThreadSafeCollection
3.032
https://ideone.com/eM1mCa
language:
C# (gmcs 5.20.1)
created:
8 years ago
visibility:
secret

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