Understanding comparators

A heap data structure is a binary tree that follows the heap property such that the parent node is either greater (max-heap) or smaller (min heap) than its children. Instances of primitive data types like integers, characters, etc, can be compared to each other using the relational operators < and > to establish the greater and smaller relationships.

However, some problems require us to store more complex data structures like arrays, lists, maps and class objects in a heap. To store anything other than the primitive data types in a heap, we need to define a comparison rule that defines ordering between two items using a comparator.