Java’s TreeSet and TreeMap are part of the Java Collections Framework and are implemented using Red-Black Trees. These data structures are invaluable when working with sorted data, range-based queries, or maintaining relationships between keys and values. In this blog, we’ll explore their implementation, usage, and the types of problems they solve, with practical examples.
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1. TreeSet
Overview
A TreeSet is a NavigableSet implementation backed by a TreeMap.
It maintains elements in sorted order, either in their natural ordering (defined by the Comparable interface) or a custom ordering (via a Comparator).
Duplicate elements are not allowed.
Key Features
Sorted Storage: Elements are always kept in sorted order.
Unique Elements: Duplicate elements are ignored.
Efficient Operations: Add, remove, and search operations have O(logn) complexity.
Implementation
Internally, TreeSet is a wrapper around TreeMap. When you add an element to a TreeSet, it stores the element as the key in a TreeMap with a dummy value.
