Hi there! I have a few questions after watching the lecture today. Question 9, how is the time complexity for the brute force O(n^(2k)) does it come from us having a total of n^2 total combinations and choosing subarrays is Subarray^k ? Also, I didn't really understand when it was mentioned an easier to prove time complexity of O(2^n) There were a few questions that were not answered in the lecture, (e.g. Question 9 efficient method, Question 5 efficient method) will there be a sample answer so that we can see how we should answer ? Thanks!