Add A000290 Squares Sequence (TheAlgorithms#285)

OleksiiHe · siriak · web-flow · commit bcd50b8ad6c5 · 2022-01-27T17:27:17.000+02:00
Co-authored-by: Oleksii Herasymenko &lt;oherasy@softserveinc.com&gt;
Co-authored-by: Andrii Siriak &lt;siryaka@gmail.com&gt;
diff --git a/Algorithms.Tests/Sequences/SquaresSequenceTests.cs b/Algorithms.Tests/Sequences/SquaresSequenceTests.cs
@@ -0,0 +1,19 @@
+﻿using System.Linq;
+using System.Numerics;
+using Algorithms.Sequences;
+using FluentAssertions;
+using NUnit.Framework;
+
+namespace Algorithms.Tests.Sequences
+{
+    public class SquaresSequenceTests
+    {
+        [Test]
+        public void First10ElementsCorrect()
+        {
+            var sequence = new SquaresSequence().Sequence.Take(10);
+            sequence.SequenceEqual(new BigInteger[] { 0, 1, 4, 9, 16, 25, 36, 49, 64, 81 })
+                .Should().BeTrue();
+        }
+    }
+}
diff --git a/Algorithms/Sequences/SquaresSequence.cs b/Algorithms/Sequences/SquaresSequence.cs
@@ -0,0 +1,36 @@
+﻿using System.Collections.Generic;
+using System.Numerics;
+
+namespace Algorithms.Sequences
+{
+    /// <summary>
+    ///     <para>
+    ///         Sequence of square numbers.
+    ///     </para>
+    ///     <para>
+    ///         Wikipedia: https://wikipedia.org/wiki/Square_number.
+    ///     </para>
+    ///     <para>
+    ///         OEIS: http://oeis.org/A000290.
+    ///     </para>
+    /// </summary>
+    public class SquaresSequence : ISequence
+    {
+        /// <summary>
+        /// Gets sequence of square numbers.
+        /// </summary>
+        public IEnumerable<BigInteger> Sequence
+        {
+            get
+            {
+                var n = new BigInteger(0);
+
+                while (true)
+                {
+                    yield return n * n;
+                    n++;
+                }
+            }
+        }
+    }
+}
diff --git a/README.md b/README.md
@@ -102,6 +102,7 @@ This repository contains algorithms and data structures implemented in C# for ed
     * [A000045 Fibonacci](./Algorithms/Sequences/FibonacciSequence.cs)
     * [A000108 Catalan](./Algorithms/Sequences/CatalanSequence.cs)
     * [A000142 Factorial](./Algorithms/Sequences/FactorialSequence.cs)
+    * [A000290 Squares](./Algorithms/Sequences/SquaresSequence.cs)
     * [A000578 Cubes](./Algorithms/Sequences/CubesSequence.cs)
     * [A001462 Golomb's](./Algorithms/Sequences/GolombsSequence.cs)
     * [A001478 Negative Integers](./Algorithms/Sequences/NegativeIntegersSequence.cs)
