Unexpected Behavior in Merge Sort Implementation in C# - Resulting Array is Not Sorted
I'm currently implementing the merge sort algorithm in C# and have encountered a puzzling issue. My implementation sorts an array of integers, but the output is not always sorted correctly. For example, when given the input array `[5, 2, 9, 1, 5, 6]`, the output is `[1, 2, 5, 5, 9, 6]`, which is incorrect because the last element `6` is out of order. Here's the code I'm using: ```csharp public static int[] MergeSort(int[] array) { if (array.Length <= 1) return array; int mid = array.Length / 2; int[] left = MergeSort(array.Take(mid).ToArray()); int[] right = MergeSort(array.Skip(mid).ToArray()); return Merge(left, right); } private static int[] Merge(int[] left, int[] right) { int[] result = new int[left.Length + right.Length]; int i = 0, j = 0, k = 0; while (i < left.Length && j < right.Length) { if (left[i] <= right[j]) { result[k++] = left[i++]; } else { result[k++] = right[j++]; } } while (i < left.Length) { result[k++] = left[i++]; } while (j < right.Length) { result[k++] = right[j++]; } return result; } ``` I’ve tried debugging the merge step, and I believe the logic is sound. I also checked the base case of the recursion to ensure it's correct. I'm using .NET Core 3.1 and C# 8.0. Any ideas why the resulting array might be incorrectly sorted? Could it be an issue with how I'm merging the arrays, or is there something I'm missing in the recursive calls?