From ebb998ea630dbbc27e3e3d6e0f8bf1757afefff7 Mon Sep 17 00:00:00 2001
From: Jc Calayag <138150245+Jccqt@users.noreply.github.com>
Date: Thu, 17 Jul 2025 17:30:51 +0800
Subject: [PATCH] Add Naive shuffling algorithm

---
 .../Shufflers/NaiveShufflerTests.cs           | 60 +++++++++++++++++++
 Algorithms/Shufflers/NaiveShuffler.cs         | 31 ++++++++++
 README.md                                     |  1 +
 3 files changed, 92 insertions(+)
 create mode 100644 Algorithms.Tests/Shufflers/NaiveShufflerTests.cs
 create mode 100644 Algorithms/Shufflers/NaiveShuffler.cs

diff --git a/Algorithms.Tests/Shufflers/NaiveShufflerTests.cs b/Algorithms.Tests/Shufflers/NaiveShufflerTests.cs
new file mode 100644
index 00000000..9fc9ba00
--- /dev/null
+++ b/Algorithms.Tests/Shufflers/NaiveShufflerTests.cs
@@ -0,0 +1,60 @@
+using Algorithms.Shufflers;
+using Algorithms.Tests.Helpers;
+using FluentAssertions;
+using NUnit.Framework;
+using System;
+
+namespace Algorithms.Tests.Shufflers
+{
+    public static class NaiveShufflerTests
+    {
+        [Test]
+        public static void ArrayShuffled_NewArraySameSize(
+            [Random(10, 1000, 100, Distinct = true)]
+            int n)
+        {
+            // Arrange
+            var shuffler = new NaiveShuffler<int>();
+            var (correctArray, testArray) = RandomHelper.GetArrays(n);
+
+            // Act
+            shuffler.Shuffle(testArray);
+
+            // Assert
+            testArray.Length.Should().Be(correctArray.Length);
+        }
+
+        [Test]
+        public static void ArrayShuffled_NewArraySameValues(
+            [Random(10, 1000, 100, Distinct = true)]
+            int n)
+        {
+            // Arrange
+            var shuffler = new NaiveShuffler<int>();
+            var (correctArray, testArray) = RandomHelper.GetArrays(n);
+
+            // Act
+            shuffler.Shuffle(testArray);
+
+            // Assert
+            testArray.Should().BeEquivalentTo(correctArray);
+        }
+
+        [Test]
+        public static void ArrayShuffled_NewArraySameShuffle(
+            [Random(0, 1000, 2, Distinct = true)] int n,
+            [Random(1000, 10000, 5, Distinct = true)] int seed)
+        {
+            // Arrange
+            var shuffle = new LinqShuffler<int>();
+            var (correctArray, testArray) = RandomHelper.GetArrays(n);
+
+            // Act
+            shuffle.Shuffle(testArray, seed);
+            shuffle.Shuffle(correctArray, seed);
+
+            // Assert
+            correctArray.Should().BeEquivalentTo(testArray, options => options.WithStrictOrdering());
+        }
+    }
+}
diff --git a/Algorithms/Shufflers/NaiveShuffler.cs b/Algorithms/Shufflers/NaiveShuffler.cs
new file mode 100644
index 00000000..94e10d18
--- /dev/null
+++ b/Algorithms/Shufflers/NaiveShuffler.cs
@@ -0,0 +1,31 @@
+using System;
+
+namespace Algorithms.Shufflers
+{
+    /// <summary>
+    ///     Naive Shuffle is a simple and incorrect shuffling algorithm
+    ///     that randomly swaps every element with any other element in the array.
+    /// </summary>
+    /// <typeparam name="T">Type array input.</typeparam>
+    public class NaiveShuffler<T> : IShuffler<T>
+    {
+        /// <summary>
+        /// First, it loop from 0 to n - 1.
+        /// Next, it will randomly pick any j in the array.
+        /// Lastly, it will swap array[i] with array[j].
+        /// </summary>
+        /// <param name="array">Array to shuffle.</param>
+        /// <param name="seed">Random generator seed. Used to repeat the shuffle.</param>
+        public void Shuffle(T[] array, int? seed = null)
+        {
+            var random = seed is null ? new Random() : new Random(seed.Value);
+            for(int i = 0; i < array.Length; i++)
+            {
+                int j = random.Next(array.Length);
+                T temp = array[i];
+                array[i] = array[j];
+                array[j] = temp;
+            }
+        }
+    }
+}
diff --git a/README.md b/README.md
index 9f1fef06..bd8490d3 100644
--- a/README.md
+++ b/README.md
@@ -149,6 +149,7 @@ find more than one implementation for the same objective but using different alg
   * [Shufflers](./Algorithms/Shufflers)
     * [Fisher-Yates Shuffler](./Algorithms/Shufflers/FisherYatesShuffler.cs)
     * [LINQ Shuffler](./Algorithms/Shufflers/LinqShuffler.cs)
+    * [Naive Shuffler](./Algorithms/Shufflers/NaiveShuffler.cs)
   * [Sequences](./Algorithms/Sequences)
     * [A000002 Kolakoski](./Algorithms/Sequences/KolakoskiSequence.cs)
     * [A000004 Zero](./Algorithms/Sequences/ZeroSequence.cs)