Persistent Data Structure
Domain: Data Structures
🎯 Motivation
A structure that preserves old versions after updates. Common in functional programming, version control, and undo features.
📋 Concrete Example
Updating a persistent list creates a new version that shares unchanged parts with the old version. Both old and new coexist. Like Git branches sharing common history.
🔗 Analogy
A sketchbook where each page builds on the previous. You never erase; each new page is a new version. Old pages (versions) are preserved and share most of the drawing.