avail/avail.utility.structures/LeftistHeap

LeftistHeap

sealed class LeftistHeap<Value : Comparable<Value>>

A LeftistHeap is a persistent (immutable) priority queue. The first operation is O(1), and with and withoutFirst are O(log(n)). The latter two also produce a new LeftistHeap without modifying the original.

A LeftistHeap is either a leftistLeaf having no elements, or a LeftistInternal containing the heap's minimum (the values of the heap must be Comparable), a left subtree, and a right subtree. The rank of a heap is the length of the shortest path to a leaf. The rank of a heap's right subtree is always less than or equal to the rank of the heap's left subtree. Therefore, the shortest path to a leaf can always be found along the right spine. In fact, the rank can be defined as zero for a leaf, or the right subtree's rank + 1.

Author

Mark van Gulik

Parameters

rank

The rank of the heap, which is the number of values along the right spine.

size

The number of values in the heap.

Properties

first

abstract val first: Value

The minimum value of this heap.

isEmpty

val isEmpty: Boolean

Whether this heap is empty.

rank

val rank: Int

size

val size: Int

withoutFirst

abstract val withoutFirst: LeftistHeap<Value>

A heap having all but its minimum value.

Functions

merge

abstract fun merge(another: LeftistHeap<Value>): LeftistHeap<Value>

Merge this heap with another.

toList

fun toList(): List<Value>

Collect the heap's elements in a List in arbitrary order.

with

abstract fun with(newValue: Value): LeftistHeap<Value>

A heap with one more element.

without

abstract fun without(value: Value): LeftistHeap<Value>

Create a heap with a specific element removed. This is particularly efficient (O(log(N))) when the element is the minimal element, although withoutFirst is the preferred form.