#string

Tries (Prefix Trees)

Introduction A Trie (pronounced “try”) is a tree-like data structure used to store and search strings efficiently. Each node represents a single character, and paths from root to node spell out prefixes. It’s the data structure behind autocomplete, spell checkers, and IP routing tables. The name comes from “retrieval” — tries are optimized for looking up strings by prefix. Unlike a hash table which gives you O(1) lookup for exact keys, a trie gives you O(m) lookup (where m is the key length) plus the ability to find all keys that share a prefix. Read more →

March 31, 2026