TikTok Frontend Intern interview questions

Question: You are tasked with simulating a supermarket self-checkout system. The supermarket has N checkout counters, each with its own queue. Customers arrive one by one, each with a certain number of items. A counter processes one item per minute. Rules: 1. A customer always chooses the counter with the shortest queue length (if there’s a tie, choose the one with the smallest counter ID). 2. When a customer is being served, their remaining items decrease by 1 each minute. 3. If a counter’s queue becomes empty, it is immediately available for the next arriving customer. Input: • N — number of checkout counters. • A list of customers, where each customer is represented as (arrival_time, items). Output: • A list showing the finish time for each customer in the order they arrived. N = 2 Customers = [(0, 5), (0, 2), (1, 3), (4, 1)] Output: [5, 2, 6, 5] Explanation: • Time 0: Customer 1 goes to Counter 1, Customer 2 goes to Counter 2. • Time 1: Customer 3 arrives, joins Counter 2 (shorter queue). • Time 4: Customer 4 arrives, joins Counter 1 (shorter queue).

SQL script that takes the maximum of a value in one table, based on a join of data from another table