Amazon's systems generate billions of log entries daily. This problem teaches you to write a multi-criteria custom comparator, which is a skill that comes up whenever you need to sort objects by more than rule.
You'll practice partitioning data into groups and sorting one group with a comparator that handles ties. After solving this, you'll recognize the partition-then-sort pattern instantly. Amazon uses this as a warm-up because it tests careful reading and clean comparator logic in under minutes.