Bucket Sort: .NET 10, corrected bucket formula and bubble sort, copy-per-call benchmark (#2371)

Targets net10.0 with BenchmarkDotNet 0.15.8 and MSTest 4.5.2. SortArray now scales each value's distance from the minimum to the bucket count with long arithmetic and checks the base case first; BubbleSort compares neighbours; SortArrayOptimized uses a long range and a nullable node. The benchmark moves to BucketSortBenchmarks, copies its input per call and adds an Array.Sort baseline. New edge-case, full-range and random tests.

Author: vladimir-pecanac-main

csharp-algorithms/BucketSort/BucketSort/BucketSort.csproj

@@ -2,13 +2,13 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.13.1" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.15.8" />
   </ItemGroup>
 
 </Project>

csharp-algorithms/BucketSort/BucketSort/BucketSortBenchmarks.cs

@@ -0,0 +1,50 @@
+using BenchmarkDotNet.Attributes;
+
+namespace BucketSort;
+
+public class BucketSortBenchmarks
+{
+    private readonly BucketSortMethods _sorter = new();
+    private int[] _source = [];
+    private int[] _work = [];
+
+    [Params(200, 2_000, 20_000)]
+    public int Size { get; set; }
+
+    [Params("Random", "Sorted")]
+    public string Input { get; set; } = "Random";
+
+    [GlobalSetup]
+    public void Setup()
+    {
+        _source = Input == "Random"
+            ? BucketSortMethods.CreateRandomArray(Size)
+            : BucketSortMethods.CreateSortedArray(Size);
+        _work = new int[Size];
+    }
+
+    [Benchmark]
+    public int[] SortArray()
+    {
+        _source.CopyTo(_work, 0);
+
+        return _sorter.SortArray(_work);
+    }
+
+    [Benchmark]
+    public int[] SortArrayOptimized()
+    {
+        _source.CopyTo(_work, 0);
+
+        return _sorter.SortArrayOptimized(_work);
+    }
+
+    [Benchmark(Baseline = true)]
+    public int[] ArraySort()
+    {
+        _source.CopyTo(_work, 0);
+        Array.Sort(_work);
+
+        return _work;
+    }
+}

csharp-algorithms/BucketSort/BucketSort/BucketSortMethods.cs

@@ -1,155 +1,142 @@
-using BenchmarkDotNet.Attributes;
+namespace BucketSort;
 
-namespace BucketSort
+public class BucketSortMethods
 {
-    public class BucketSortMethods
+    public int[] SortArray(int[] array)
     {
-        public IEnumerable<object[]> SampleArrays()
+        if (array.Length <= 1)
         {
-            yield return new object[] { CreateRandomArray(200), "Small Unsorted" };
-            yield return new object[] { CreateRandomArray(2000), "Medium Unsorted" };
-            yield return new object[] { CreateRandomArray(20000), "Large Unsorted" };
-            yield return new object[] { CreateSortedArray(200), "Small Sorted" };
-            yield return new object[] { CreateSortedArray(2000), "Medium Sorted" };
-            yield return new object[] { CreateSortedArray(20000), "Large Sorted" };
+            return array;
         }
 
-        [Benchmark]
-        [ArgumentsSource(nameof(SampleArrays))]
-        public int[] SortArray(int[] array, string arrayName)
-        {
-            List<int> sortedList = new List<int>();
-            var minValue = array[0];
-            var maxValue = array[0];
-
-            if (array == null || array.Length <= 1)
-            {
-                return array;
-            }
+        List<int> sortedList = [];
+        var minValue = array[0];
+        var maxValue = array[0];
 
-            for (int i = 1; i < array.Length; i++)
-            {
-                if (array[i] > maxValue)
-                    maxValue = array[i];
-                if (array[i] < minValue)
-                    minValue = array[i];
-            }
+        for (int i = 1; i < array.Length; i++)
+        {
+            if (array[i] > maxValue)
+                maxValue = array[i];
+            if (array[i] < minValue)
+                minValue = array[i];
+        }
 
-            var numberOfBuckets = maxValue - minValue + 1;
-            List<int>[] bucket = new List<int>[numberOfBuckets];
+        var numberOfBuckets = array.Length;
+        var range = (long)maxValue - minValue + 1;
+        List<int>[] bucket = new List<int>[numberOfBuckets];
 
-            for (int i = 0; i < numberOfBuckets; i++) 
-            {
-                bucket[i] = new List<int>();
-            }
-               
-            for (int i = 0; i < array.Length; i++)
-            {
-                var selectedBucket = (array[i] / numberOfBuckets);
-                bucket[selectedBucket].Add(array[i]);
-            }
+        for (int i = 0; i < numberOfBuckets; i++)
+        {
+            bucket[i] = [];
+        }
 
-            for (int i = 0; i < numberOfBuckets; i++)
-            {
-                int[] temp = BubbleSort(bucket[i]);
-                sortedList.AddRange(temp);
-            }
+        for (int i = 0; i < array.Length; i++)
+        {
+            var selectedBucket = (int)((array[i] - (long)minValue) * numberOfBuckets / range);
+            bucket[selectedBucket].Add(array[i]);
+        }
 
-            return sortedList.ToArray();
+        for (int i = 0; i < numberOfBuckets; i++)
+        {
+            int[] temp = BubbleSort(bucket[i]);
+            sortedList.AddRange(temp);
         }
 
-        public static int[] BubbleSort(List<int> listInput)
+        return sortedList.ToArray();
+    }
+
+    public static int[] BubbleSort(List<int> listInput)
+    {
+        for (int i = 0; i < listInput.Count - 1; i++)
         {
-            for (int i = 0; i < listInput.Count; i++)
+            for (int j = 0; j < listInput.Count - i - 1; j++)
             {
-                for (int j = 0; j < listInput.Count; j++)
+                if (listInput[j] > listInput[j + 1])
                 {
-                    if (listInput[i] < listInput[j])
-                    {
-                        var temp = listInput[i];
-                        listInput[i] = listInput[j];
-                        listInput[j] = temp;
-                    }
+                    var temp = listInput[j];
+                    listInput[j] = listInput[j + 1];
+                    listInput[j + 1] = temp;
                 }
             }
-            return listInput.ToArray();
         }
 
+        return listInput.ToArray();
+    }
 
-        [Benchmark]
-        [ArgumentsSource(nameof(SampleArrays))]
-        public int[] SortArrayOptimized(int[] array, string arrayName)
+    public int[] SortArrayOptimized(int[] array)
+    {
+        if (array.Length <= 1)
         {
-            if (array == null || array.Length <= 1)
-            {
-                return array;
-            }
+            return array;
+        }
 
-            int maxValue = array[0]; 
-            int minValue = array[0];
+        int maxValue = array[0];
+        int minValue = array[0];
 
-            for (int i = 1; i < array.Length; i++)
+        for (int i = 1; i < array.Length; i++)
+        {
+            if (array[i] > maxValue)
             {
-                if (array[i] > maxValue)
-                {
-                    maxValue = array[i];
-                }
+                maxValue = array[i];
+            }
 
-                if (array[i] < minValue)
-                {
-                    minValue = array[i];
-                }
+            if (array[i] < minValue)
+            {
+                minValue = array[i];
             }
+        }
 
-            LinkedList<int>[] bucket = new LinkedList<int>[maxValue - minValue + 1];
+        var range = (long)maxValue - minValue + 1;
+        LinkedList<int>[] bucket = new LinkedList<int>[range];
 
-            for (int i = 0; i < array.Length; i++)
+        for (int i = 0; i < array.Length; i++)
+        {
+            if (bucket[array[i] - minValue] == null)
             {
-                if (bucket[array[i] - minValue] == null)
-                {
-                    bucket[array[i] - minValue] = new LinkedList<int>();
-                }
-
-                bucket[array[i] - minValue].AddLast(array[i]);
+                bucket[array[i] - minValue] = new LinkedList<int>();
             }
 
-            var index = 0;
-            for (int i = 0; i < bucket.Length; i++)
+            bucket[array[i] - minValue].AddLast(array[i]);
+        }
+
+        var index = 0;
+
+        for (int i = 0; i < bucket.Length; i++)
+        {
+            if (bucket[i] != null)
             {
-                if (bucket[i] != null)
+                LinkedListNode<int>? node = bucket[i].First;
+
+                while (node != null)
                 {
-                    LinkedListNode<int> node = bucket[i].First;
-
-                    while (node != null)
-                    {
-                        array[index] = node.Value;
-                        node = node.Next; 
-                        index++;
-                    }
+                    array[index] = node.Value;
+                    node = node.Next;
+                    index++;
                 }
             }
-            return array;
         }
 
-        public static int[] CreateRandomArray(int size)
-        {
-            var array = new int[size];
-            var rand = new Random();
+        return array;
+    }
 
-            for (int i = 0; i < size; i++)
-                array[i] = rand.Next(1, size);
+    public static int[] CreateRandomArray(int size)
+    {
+        var array = new int[size];
+        var rand = new Random();
 
-            return array;
-        }
+        for (int i = 0; i < size; i++)
+            array[i] = rand.Next(1, size);
 
-        public static int[] CreateSortedArray(int size)
-        {
-            var array = new int[size];
+        return array;
+    }
 
-            for (int i = 0; i < size; i++)
-                array[i] = i;
+    public static int[] CreateSortedArray(int size)
+    {
+        var array = new int[size];
 
-            return array;
-        }
+        for (int i = 0; i < size; i++)
+            array[i] = i;
+
+        return array;
     }
 }

csharp-algorithms/BucketSort/BucketSort/Program.cs

@@ -1,4 +1,4 @@
 using BenchmarkDotNet.Running;
 using BucketSort;
 
-var summary = BenchmarkRunner.Run<BucketSortMethods>();
+BenchmarkRunner.Run<BucketSortBenchmarks>(args: args);

csharp-algorithms/BucketSort/BucketSortTests/BucketSortTests.csproj

@@ -1,17 +1,22 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="2.2.7" />
-    <PackageReference Include="MSTest.TestFramework" Version="2.2.7" />
-    <PackageReference Include="coverlet.collector" Version="3.1.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.11.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="4.5.2" />
+    <PackageReference Include="MSTest.TestFramework" Version="4.5.2" />
+    <PackageReference Include="coverlet.collector" Version="10.1.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Microsoft.VisualStudio.TestTools.UnitTesting" />
   </ItemGroup>
 
   <ItemGroup>