Perform Queries

Problem Overview

• Process q queries to manage a shipping queue, inserting package IDs and shipping groups of three in FIFO order.
• Input: list of queries as ['INSERT', id] or ['SHIP','-']; Output: for each SHIP, three IDs in queue order or 'N/A' if fewer than three.
• Queue starts empty; shipped groups must preserve original arrival order.
• Real-world context: warehouse logistics and batch shipping of packages.
• From Amazon interviews; a coding interview problem and interview question.