Data.Heap.Leftist

Leftist Heap

• the fun of programming

Data structures

data Leftist a

Constructors

Leaf

Node Rank (Leftist a) a (Leftist a)

Instances

(Eq a, Ord a) => Eq (Leftist a)

Show a => Show (Leftist a)

type Rank = Int

Creating heaps

empty :: Leftist a

Empty heap.

singleton :: a -> Leftist a

Singleton heap.

insert :: Ord a => a -> Leftist a -> Leftist a

Insertion.

>>> insert 7 (fromList [5,3]) == fromList [3,5,7]
True
>>> insert 5 empty            == singleton 5
True

fromList :: Ord a => [a] -> Leftist a

Creating a heap from a list.

>>> empty == fromList []
True
>>> singleton 'a' == fromList ['a']
True
>>> fromList [5,3] == fromList [5,3]
True

Converting to a list

toList :: Leftist a -> [a]

Creating a list from a heap. O(N)

>>> let xs = [5,3,5]
>>> length (toList (fromList xs)) == length xs
True
>>> toList empty
[]

Deleting

deleteMin :: Ord a => Leftist a -> Leftist a

Deleting the minimum element.

>>> deleteMin (fromList [5,3,7]) == fromList [5,7]
True
>>> deleteMin empty == empty
True

Checking heaps

null :: Leftist t -> Bool

See if the heap is empty.

>>> Data.Heap.Leftist.null empty
True
>>> Data.Heap.Leftist.null (singleton 1)
False

Helper functions

merge :: Ord a => Leftist a -> Leftist a -> Leftist a

Merging two heaps

>>> merge (fromList [5,3]) (fromList [5,7]) == fromList [3,5,5,7]
True

minimum :: Leftist a -> Maybe a

Finding the minimum element.

>>> minimum (fromList [3,5,1])
Just 1
>>> minimum empty
Nothing

valid :: Ord a => Leftist a -> Bool

Checking validity of a heap.

heapSort :: Ord a => Leftist a -> [a]