1. Given an array of integers that may contain duplicates, find all subsets that sum to a target value K.

2. How do you set up a Node.js server?

3. What are the methods for expanding sales and distribution?

4. How do you improve communication with trade partners?

5. You are given an array prices where prices[i] is the price of a given stock on the ith day. You want to maximize your profit by choosing a single day to buy one stock and choosing a different day in the future to sell that stock. Return the maximum profit you can achieve from this transaction. If you cannot achieve any profit, return 0.