A trie (pronounced "try") is a data structure that allows efficient lookup of words in a dictionary or set. It is particularly useful for applications where a large number of strings need to be stored and searched efficiently, such as spell checkers or auto-complete systems. Tries can also be used to implement a string pool, which can help reduce memory usage in programs that frequently use the same strings.
The name "Trie" comes from the word retrieval, which refers to the process of finding a key or value in the structure. Tries are also known as digital trees, radix trees, or prefix trees.
Trie<TKey, TValue and ConcurrentTrie<TKey, TValue> are simple implementations. These implementations do not support deletion or modification.
A Trie is a rooted tree, where each node represents a single character or a group of characters in a string. The root of the tree represents the empty string, and each path from the root to a leaf represents a complete string in the set.
Here is an example of a Trie that stores the following strings: "a", "apple", "apply", "bear", and "be".
┌───a───p───p───l───e
│ └───y
root┤
│ ┌───b───e───a───r
└───┤
└───e