1. Given an integer array nums, find a contiguous non-empty subarray within the array that has the largest product, and return the product. The test cases are generated so that the answer will fit in a 32-bit integer. A subarray is a contiguous subsequence of the array.
2. Describe the APIs, database tables, classes, functions, and implementation walkthrough for an automated parking lot.
3. consistency level in different scenarios
4. Design a car parking system.
5. Given a category tree, find a coupon for a given category. If the category has no coupon, retrieve its parent's coupon.