LLD Data Structures in Design Context: Why Some Problems Need the "Best" Result Instead of Any Result

Software systems utilize different data structures based on the engineering problem. A HashMap is ideal for fast lookup when the system knows the specific object, such as a User ID. Conversely, a Heap is designed for continuous decision-making when the system must determine the best choice among many options. Examples include assigning the best driver in ride-sharing apps or prioritizing critical alerts and task scheduling, where the system decides what happens next instead of retrieving known data.