Merge pull request #8 from guitarrapc/flaststablesort

feat: add FastStableSort

Author: guitarrapc

sandbox/DotnetFiles/FlashSortStats.cs

@@ -0,0 +1,35 @@
+#:sdk Microsoft.NET.Sdk
+#:property TargetFramework=net10.0
+#:project ../../src/SortAlgorithm
+using SortAlgorithm.Algorithms;
+using SortAlgorithm.Contexts;
+
+foreach (var n in new[] { 17, 20, 50, 100 })
+{
+    Console.WriteLine($"=== n={n} ===");
+
+    // Sorted
+    {
+        var stats = new StatisticsContext();
+        var sorted = Enumerable.Range(0, n).ToArray();
+        FlashSort.Sort(sorted.AsSpan(), stats);
+        Console.WriteLine($"  Sorted   : Compares={stats.CompareCount}, Writes={stats.IndexWriteCount}, Reads={stats.IndexReadCount}, Swaps={stats.SwapCount}");
+    }
+
+    // Reversed
+    {
+        var stats = new StatisticsContext();
+        var reversed = Enumerable.Range(0, n).Reverse().ToArray();
+        FlashSort.Sort(reversed.AsSpan(), stats);
+        Console.WriteLine($"  Reversed : Compares={stats.CompareCount}, Writes={stats.IndexWriteCount}, Reads={stats.IndexReadCount}, Swaps={stats.SwapCount}");
+    }
+
+    // Random (multiple runs)
+    for (var seed = 0; seed < 3; seed++)
+    {
+        var stats = new StatisticsContext();
+        var random = Enumerable.Range(0, n).OrderBy(_ => seed * 1000 + Guid.NewGuid().GetHashCode()).ToArray();
+        FlashSort.Sort(random.AsSpan(), stats);
+        Console.WriteLine($"  Random{seed}  : Compares={stats.CompareCount}, Writes={stats.IndexWriteCount}, Reads={stats.IndexReadCount}, Swaps={stats.SwapCount}");
+    }
+}

sandbox/DotnetFiles/FlatStableSortStats.cs

@@ -0,0 +1,35 @@
+#:sdk Microsoft.NET.Sdk
+#:property TargetFramework=net10.0
+#:project ../../src/SortAlgorithm
+using SortAlgorithm.Algorithms;
+using SortAlgorithm.Contexts;
+
+foreach (var n in new[] { 10, 20, 50, 100 })
+{
+    Console.WriteLine($"=== n={n} ===");
+
+    // Sorted
+    {
+        var stats = new StatisticsContext();
+        var sorted = Enumerable.Range(0, n).ToArray();
+        FlatStableSort.Sort(sorted.AsSpan(), stats);
+        Console.WriteLine($"  Sorted   : Compares={stats.CompareCount}, Writes={stats.IndexWriteCount}, Reads={stats.IndexReadCount}, Swaps={stats.SwapCount}");
+    }
+
+    // Reversed
+    {
+        var stats = new StatisticsContext();
+        var reversed = Enumerable.Range(0, n).Reverse().ToArray();
+        FlatStableSort.Sort(reversed.AsSpan(), stats);
+        Console.WriteLine($"  Reversed : Compares={stats.CompareCount}, Writes={stats.IndexWriteCount}, Reads={stats.IndexReadCount}, Swaps={stats.SwapCount}");
+    }
+
+    // Random (multiple runs)
+    for (var seed = 0; seed < 3; seed++)
+    {
+        var stats = new StatisticsContext();
+        var random = Enumerable.Range(0, n).OrderBy(_ => seed * 1000 + Guid.NewGuid().GetHashCode()).ToArray();
+        FlatStableSort.Sort(random.AsSpan(), stats);
+        Console.WriteLine($"  Random{seed}  : Compares={stats.CompareCount}, Writes={stats.IndexWriteCount}, Reads={stats.IndexReadCount}, Swaps={stats.SwapCount}");
+    }
+}

src/SortAlgorithm.Benchmark/MergeBenchmark.cs

@@ -25,6 +25,7 @@ public class MergeBenchmark
     private int[] _spinvariantArray = default!;
     private int[] _spinArray = default!;
     private int[] _glidesortArray = default!;
+    private int[] _flatstableArray = default!;
 
     [IterationSetup]
     public void Setup()
@@ -44,6 +45,7 @@ public void Setup()
         _spinvariantArray = BenchmarkData.GenerateIntArray(Size, Pattern);
         _spinArray = BenchmarkData.GenerateIntArray(Size, Pattern);
         _glidesortArray = BenchmarkData.GenerateIntArray(Size, Pattern);
+        _flatstableArray = BenchmarkData.GenerateIntArray(Size, Pattern);
     }
 
     [Benchmark(Baseline = true)]
@@ -135,4 +137,10 @@ public void Glidesort()
     {
         SortAlgorithm.Algorithms.Glidesort.Sort(_glidesortArray.AsSpan());
     }
+
+    [Benchmark]
+    public void FlatStableSort()
+    {
+        SortAlgorithm.Algorithms.FlatStableSort.Sort(_flatstableArray.AsSpan());
+    }
 }