Suppose you are designing a system for buying and selling stocks using a continuous limit order book strategy, as described in the beginning of this chapter. Describe how to use priority queues to process such buy and sell orders, including those that can be processed immediately and those that have some or all of their shares needing to wait until some future match to be processed. You don’t need to list all pending buy and sell orders, but you do need to always display the pending buy order(s) with the highest and lowest prices and the pending order(s) with the highest and lowest prices. You may assume that buy and sell orders are never cancelled and remain in the system until they are matched. Describe a system that can process buy and sell orders in amortized O(log n) time, where n is the number of orders in the system.