PrefixTree

class PrefixTree<K, V>(mapFactory: () -> MutableMap<K, PrefixTree<K, V>> = { mutableMapOf() })

A prefix tree, with amortized O(1) access time, amortized O(1) insertion time O(1), amortized O(1) removal time, and O(n) prune time. Thread-safe iff the internal transition tables, supplied by the factory, are thread-safe.

Author

Todd L Smith

Constructors

PrefixTree

fun <K, V> PrefixTree(mapFactory: () -> MutableMap<K, PrefixTree<K, V>> = { mutableMapOf() })

Types

Companion

object Companion

Functions

get

operator fun get(key: Iterable<K>): V?

Fetch the value associated with the specified key, if any.

getOrPut

fun getOrPut(key: Iterable<K>, producer: () -> V): V

Fetch the value associated with the specified key, or install the value produced by applying producer if no value was available.

payloads

fun payloads(key: Iterable<K>): List<V>

Fetch every payload stored under an improper suffix of the specified key, ordered lexicographically by key.

prune

fun prune()

Remove all paths from the receiver that do not lead to payloads.

remove

fun remove(key: Iterable<K>): V?

Remove the specified key and any associated value from the receiver. Fast, because it does not alter the shape of the tree.

set

operator fun set(key: Iterable<K>, value: V): V?

Insert a new key-value pair into the receiver, replacing any existing value associated with the specified key.

toString

open override fun toString(): String

Extensions

get

inline operator fun <V> PrefixTree<Int, V>.get(key: String): V?

Convenience getter for using string-keyed prefix trees.

getOrPut

inline fun <V> PrefixTree<Int, V>.getOrPut(key: String, noinline producer: () -> V): V

Convenience getter/setter for using string-keyed prefix trees.

payloads

inline fun <V> PrefixTree<Int, V>.payloads(key: String): List<V>

Convenience accumulator for using string-keyed prefix trees.

set

inline operator fun <V> PrefixTree<Int, V>.set(key: String, value: V): V?

Convenience setter for using string-keyed prefix trees.