How to Safely Rotate an Immutable List in C# Without Creating a New Instance?
I've been struggling with this for a few days now and could really use some help. I'm working on a project and hit a roadblock. I'm working with an immutable list in C# (specifically using `System.Collections.Immutable.ImmutableArray<T>`), and I need to rotate the elements of this list by a given number of positions. However, since `ImmutableArray<T>` does not allow modifications to its contents, I want to ensure that I can perform this rotation without creating a new instance each time. I've tried manipulating the indices using modular arithmetic, but I'm running into confusion with how to handle cases where the rotation count exceeds the length of the array. For instance, if I have the following code: ```csharp using System; using System.Collections.Immutable; class Program { static void Main() { var originalArray = ImmutableArray.Create(1, 2, 3, 4, 5); int rotationCount = 7; // This exceeds the length of the array var rotatedArray = RotateImmutableArray(originalArray, rotationCount); Console.WriteLine(string.Join(", ", rotatedArray)); } static ImmutableArray<T> RotateImmutableArray<T>(ImmutableArray<T> array, int positions) { // Attempting to handle rotation here int len = array.Length; if (len == 0) return array; positions = positions % len; // This helps with large rotation counts return array; // Need to implement the rotation logic } } ``` Currently, I just return the original array, but I want to implement the actual rotation logic. I'm worried about performance as well, especially if the list is large. What’s the best way to do this safely and efficiently? Is there a common pattern or best practice for handling this kind of scenario in C# with immutable collections? Also, what should I do if the `positions` is negative? Any guidance would be appreciated!