.NET Code Challenges & Tips

1. Write a function in C# to determine if a given string is a palindrome, ignoring spaces, punctuation, and capitalization.

2. Implement a method that takes two sorted lists and returns a new sorted list that contains all elements from both lists without duplicates.

3. Create a function that takes an integer array and returns the maximum sum of any contiguous subarray (Kadane’s Algorithm).

4. Write a recursive function to calculate the nth Fibonacci number.

5. Implement a class that represents a basic calculator capable of performing addition, subtraction, multiplication, and division operations based on an input string in Reverse Polish Notation.

6. Write a method to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty string.

7. Create a function that merges two binary trees into a new binary tree by adding values at overlapping nodes.

8. Write a method that finds the first non-repeating character in a string and returns its index. If it doesn't exist, return -1.

9. Implement a function to check if a given string has all unique characters without using any additional data structures.

10. Write a function that takes a string as input and returns all possible subsets (the power set) of that string.