[draft] Add MergeSort exercise and docs

Author: rudironsoni

C-Sharp-Data-Structures-and-Algorithms.sln

@@ -44,6 +44,13 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		.gitignore = .gitignore
 	EndProjectSection
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Arrays", "Arrays", "{517E461B-F61E-4598-A4D9-D1ABAE070CE5}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Sort", "Sort", "{3D3FEA4A-376A-45C5-BED1-517954BA5782}"
+	ProjectSection(SolutionItems) = preProject
+		Docs\Exercises\Arrays\Sort\MergeSort.md = Docs\Exercises\Arrays\Sort\MergeSort.md
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -96,5 +103,7 @@ Global
 		{DF8A6048-EC35-4A12-9E18-DFE8AAEE1315} = {A66DB0A9-94B4-4591-84D7-1B4C64344EFD}
 		{52019907-5924-4F1A-86D7-1B0C1FC9CDD7} = {8F7EDDF0-E9FC-4D7D-8DBE-3C898C8798B9}
 		{D523E1B0-B30E-44C9-936C-D45A6F34191E} = {8F7EDDF0-E9FC-4D7D-8DBE-3C898C8798B9}
+		{517E461B-F61E-4598-A4D9-D1ABAE070CE5} = {D523E1B0-B30E-44C9-936C-D45A6F34191E}
+		{3D3FEA4A-376A-45C5-BED1-517954BA5782} = {517E461B-F61E-4598-A4D9-D1ABAE070CE5}
 	EndGlobalSection
 EndGlobal

Docs/Exercises/Arrays/Sort/MergeSort.md

@@ -0,0 +1,22 @@
+namespace Exercises.Arrays;
+
+public static partial class Sort
+{
+    public static int[][] MergeSort(int[][] intervals)
+    {
+        intervals = intervals.OrderBy(a => a[0]).ToArray();
+        int st = intervals[0][0], ed = intervals[0][1];
+        var ans = new List<int[]>();
+        for (int i = 1; i < intervals.Length; ++i) {
+            if (ed < intervals[i][0]) {
+                ans.Add(new int[] { st, ed });
+                st = intervals[i][0];
+                ed = intervals[i][1];
+            } else {
+                ed = Math.Max(ed, intervals[i][1]);
+            }
+        }
+        ans.Add(new int[] { st, ed });
+        return ans.ToArray();
+    }
+}

Exercises/Exercises/Arrays/Sort.MergeSort.cs

@@ -0,0 +1,33 @@
+using FluentAssertions;
+
+namespace ExercisesTests.Arrays.Sort;
+
+public class MergeSortTests
+{
+    public static IEnumerable<object[]> TestData()
+    {
+        yield return
+        [
+            new int[][] {[1, 3], [2, 6], [8, 10], [15,18]},
+            new int[][] {[1,6],[8,10],[15,18]},
+        ];
+
+        yield return
+        [
+            new int[][] {[1,4],[4,5]},
+            new int[][] {[1,5]},
+        ];
+    }
+
+    [Theory]
+    [MemberData(nameof(TestData))]
+    public void Test1(int[][] intervals, int[][] expected)
+    {
+        // Arrange
+        // Act
+        var result = Exercises.Arrays.Sort.MergeSort(intervals);
+
+        // Assert
+        result.Should().BeEquivalentTo(expected);
+    }
+}

Exercises/Exercises/Class1.cs

@@ -10,6 +10,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+        <PackageReference Include="FluentAssertions" Version="6.12.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0"/>
         <PackageReference Include="xunit" Version="2.4.2"/>
         <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
@@ -21,5 +22,9 @@
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>
     </ItemGroup>
+    
+    <ItemGroup>
+        <ProjectReference Include="..\Exercises\Exercises.csproj"/>
+    </ItemGroup>
 
 </Project>