NAME¶
Tree::RedBlack - Perl implementation of Red/Black tree, a type of balanced tree.
SYNOPSIS¶
use Tree::RedBlack;
my $t = new Tree::RedBlack;
$t->insert(3, 'cat');
$t->insert(4, 'dog');
my $v = $t->find(4);
my $min = $t->min;
my $max = $t->max;
$t->delete(3);
$t->print;
DESCRIPTION¶
This is a perl implementation of the Red/Black tree algorithm found in the book
"Algorithms", by Cormen, Leiserson & Rivest (more commonly known
as "CLR" or "The White Book"). A Red/Black tree is a
binary tree which remains "balanced"- that is, the longest length
from root to a node is at most one more than the shortest such length. It is
fairly efficient; no operation takes more than O(lg(n)) time.
A Tree::RedBlack object supports the following methods:
- new ()
- Creates a new RedBlack tree object.
- root ()
- Returns the root node of the tree. Note that this will
either be undef if no nodes have been added to the tree, or a
Tree::RedBlack::Node object. See the Tree::RedBlack::Node manual page for
details on the Node object.
- cmp (&)
- Use this method to set a comparator subroutine. The tree
defaults to lexical comparisons. This subroutine should be just like a
comparator subroutine to sort, except that it doesn't do the $a, $b trick;
the two elements to compare will just be the first two items on the
stack.
- insert ($;$)
- Adds a new node to the tree. The first argument is the key
of the node, the second is its value. If a node with that key already
exists, its value is replaced with the given value and the old value is
returned. Otherwise, undef is returned.
- delete ($)
- The argument should be either a node object to delete or
the key of a node object to delete. WARNING!!! THIS STILL HAS BUGS!!!
- find ($)
- Searches the tree to find the node with the given key.
Returns the value of that node, or undef if a node with that key isn't
found. Note, in particular, that you can't tell the difference between
finding a node with value undef and not finding a node at all. If you want
to determine if a node with a given key exists, use the node method,
below.
- node ($)
- Searches the tree to find the node with the given key.
Returns that node object if it is found, undef otherwise. The node object
is a Tree::RedBlack::Node object.
- min ()
- Returns the node with the minimal key.
- max ()
- Returns the node with the maximal key.
AUTHOR¶
Benjamin Holzman <bholzman@earthlink.net>
SEE ALSO¶
Tree::RedBlack::Node