Optimize dictionary lookups in C#

README.md

@@ -12,6 +12,7 @@ For the latest results (run on my machine), see the article's [performance resul
 
 Thanks to these contributors for additional language versions:
 
+* C#: [John Taylor](https://github.com/jftuga) and [Yuriy Ostapenko](https://github.com/uncleyo)
 * Rust: [Andrew Gallant](https://github.com/BurntSushi)
 * Perl: [Charles Randall](https://github.com/charles-randall)
 * Ruby: [Bill Mill](https://github.com/llimllib), with input from [Niklas](https://github.com/nhh)

benchmark.py

@@ -29,7 +29,7 @@ def time_run(cmdline):
     ('C++', './simple-cpp', './optimized-cpp', 'optimized by Jussi Pakkanen'),
     ('Python', 'python3 simple.py', 'python3 optimized.py', ''),
     ('Ruby', 'ruby simple.rb', 'ruby optimized.rb', 'by Bill Mill'),
-    ('C#', './simple-cs', None, 'original by John Taylor'),
+    ('C#', './csharp/simple/bin/Release/net5.0/simple', './csharp/optimized/bin/Release/net5.0/optimized', 'by John Taylor and Yuriy Ostapenko'),
     ('AWK', 'gawk -f simple.awk', 'mawk -f optimized.awk', 'optimized uses `mawk`'),
     ('Forth', '../gforth/gforth-fast simple.fs', '../gforth/gforth-fast optimized.fs', ''),
     ('Shell', 'bash simple.sh', 'bash optimized.sh', 'optimized does `LC_ALL=C sort -S 2G`'),

csharp/.gitignore

@@ -0,0 +1,2 @@
+bin
+obj

csharp/optimized/Program.cs

@@ -0,0 +1,42 @@
+// Original version by John Taylor
+
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Linq;
+
+class Program
+{
+    public sealed class Ref<T> {
+        public Ref(T initialValue) {
+            Value = initialValue;
+        }
+        public T Value { get; set; }
+    }
+
+    static void Main(string[] args)
+    {
+        var counts = new Dictionary<string, Ref<int>>();
+        string line;
+        while ((line = Console.ReadLine()) != null)
+        {
+            line = line.ToLower();
+            var words = line.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+            string word;
+            for (int i = 0; i < words.Length; i++)
+            {
+                word = words[i];
+                if (!counts.TryGetValue(word, out var count)) {
+                    counts.Add(word, new Ref<int>(1));
+                } else {
+                    count.Value += 1;
+                }
+            }
+        }
+        var ordered = counts.OrderByDescending(pair => pair.Value.Value);
+        foreach (var entry in ordered)
+        {
+            Console.WriteLine("{0} {1}", entry.Key, entry.Value.Value);
+        }
+    }
+}

csharp/optimized/optimized.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>

csharp/simple/Program.cs

@@ -0,0 +1,29 @@
+// Original version by John Taylor
+
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Linq;
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        var counts = new Dictionary<string, int>();
+        string line;
+        while ((line = Console.ReadLine()) != null)
+        {
+            line = line.ToLower();
+            var words = line.Split(' ', StringSplitOptions.RemoveEmptyEntries);
+            foreach (string word in words)
+            {
+                counts[word] = counts.GetValueOrDefault(word, 0) + 1;
+            }
+        }
+        var ordered = counts.OrderByDescending(pair => pair.Value);
+        foreach (var entry in ordered)
+        {
+            Console.WriteLine("{0} {1}", entry.Key, entry.Value);
+        }
+    }
+}

csharp/simple/simple.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>

test.sh

@@ -109,9 +109,13 @@ crystal build --release simple.cr -o simple-cr
 git diff --exit-code output.txt
 
 echo C# simple
-csc -optimize -out:simple-cs simple.cs
-chmod +x simple-cs
-./simple-cs <kjvbible_x10.txt | python3 normalize.py >output.txt
+dotnet build ./csharp/simple -c Release
+./csharp/simple/bin/Release/net5.0/simple <kjvbible_x10.txt | python3 normalize.py >output.txt
+git diff --exit-code output.txt
+
+echo C# optimized
+dotnet build ./csharp/optimized -c Release
+./csharp/optimized/bin/Release/net5.0/optimized <kjvbible_x10.txt | python3 normalize.py >output.txt
 git diff --exit-code output.txt
 
 echo Swift simple