Control.Monad.Union

Monadic interface for creating a disjoint set data structure.

Documentation

data UnionM l a

Union find monad.

Instances

MonadUnion l (UnionM l)

Monad (UnionM l)

Functor (UnionM l)

MonadFix (UnionM l)

Applicative (UnionM l)

data Union a

An immutable disjoint set forest.

Constructors

Union

Fields

size :: !Int

up :: UArray Int Int

label :: Array Int a

class Monad m => MonadUnion l m | m -> l where

Methods

new :: l -> m Node

Add a new node, with a given label.

lookup :: Node -> m (Node, l)

Find the node representing a given node, and its label.

merge :: (l -> l -> (l, a)) -> Node -> Node -> m (Maybe a)

Merge two sets. The first argument is a function that takes the labels of the corresponding sets' representatives and computes a new label for the joined set. Returns Nothing if the given nodes are in the same set already.

annotate :: Node -> l -> m ()

Re-label a node.

flatten :: m ()

Flatten the disjoint set forest for faster lookups.

Instances

(MonadUnion l m, MonadTrans t, Monad (t m)) => MonadUnion l (t m)

MonadUnion l (UnionM l)

data Node

A node in a disjoint set forest.

Instances

Eq Node

Ord Node

Ix Node

run :: UnionM l a -> a

Run a union find computation.

run' :: UnionM l a -> (Union l, a)

Run a union find computation; also return the final disjoint set forest for querying.