From 0d1dc719e1cfde1434e6faebab1401fdb0209499 Mon Sep 17 00:00:00 2001
From: Divlo <contact@divlo.fr>
Date: Sat, 11 Sep 2021 18:55:46 +0200
Subject: [PATCH] feat(solutions): add `sorting-algorithms/cs/merge-sort`

---
 .../solutions/cs/merge-sort/README.md         |  3 +
 .../solutions/cs/merge-sort/Solution.cs       | 76 +++++++++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 challenges/sorting-algorithms/solutions/cs/merge-sort/README.md
 create mode 100644 challenges/sorting-algorithms/solutions/cs/merge-sort/Solution.cs

diff --git a/challenges/sorting-algorithms/solutions/cs/merge-sort/README.md b/challenges/sorting-algorithms/solutions/cs/merge-sort/README.md
new file mode 100644
index 0000000..b91d4cb
--- /dev/null
+++ b/challenges/sorting-algorithms/solutions/cs/merge-sort/README.md
@@ -0,0 +1,3 @@
+# sorting-algorithms/cs/merge-sort
+
+Created by [@Divlo](https://github.com/Divlo) on 11 September 2021.
diff --git a/challenges/sorting-algorithms/solutions/cs/merge-sort/Solution.cs b/challenges/sorting-algorithms/solutions/cs/merge-sort/Solution.cs
new file mode 100644
index 0000000..815080a
--- /dev/null
+++ b/challenges/sorting-algorithms/solutions/cs/merge-sort/Solution.cs
@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Generic;
+
+namespace Solution
+{
+    class Program
+    {
+        static void Main()
+        {
+            string line = Console.ReadLine();
+            List<int> numbers = new List<int>();
+            while ((line = Console.ReadLine()) != null)
+            {
+                numbers.Add(int.Parse(line));
+            }
+            int[] result = MergeSort(numbers.ToArray());
+            foreach (int number in result)
+            {
+                Console.WriteLine(number);
+            }
+        }
+
+        public static int[] MergeSort(int[] array)
+        {
+            if (array.Length <= 1)
+            {
+                return array;
+            }
+            int middle = array.Length / 2;
+            int[] left = new int[middle];
+            int[] right = new int[array.Length - middle];
+            for (int index = 0; index < middle; index++)
+            {
+                left[index] = array[index];
+            }
+            for (int index = middle; index < array.Length; index++)
+            {
+                right[index - middle] = array[index];
+            }
+            left = MergeSort(left);
+            right = MergeSort(right);
+            return Merge(left, right);
+        }
+
+        public static int[] Merge(int[] left, int[] right)
+        {
+            int[] result = new int[left.Length + right.Length];
+            int leftIndex = 0;
+            int rightIndex = 0;
+            for (int index = 0; index < result.Length; index++)
+            {
+                if (leftIndex >= left.Length)
+                {
+                    result[index] = right[rightIndex];
+                    rightIndex++;
+                }
+                else if (rightIndex >= right.Length)
+                {
+                    result[index] = left[leftIndex];
+                    leftIndex++;
+                }
+                else if (left[leftIndex] < right[rightIndex])
+                {
+                    result[index] = left[leftIndex];
+                    leftIndex++;
+                }
+                else
+                {
+                    result[index] = right[rightIndex];
+                    rightIndex++;
+                }
+            }
+            return result;
+        }
+    }
+}