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.IX Title "RedBlack 3pm"
.TH RedBlack 3pm "2022-10-22" "perl v5.34.0" "User Contributed Perl Documentation"
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.SH "NAME"
Tree::RedBlack \- Perl implementation of Red/Black tree, a type of balanced tree.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  use Tree::RedBlack;
\&  
\&  my $t = new Tree::RedBlack;
\&  $t\->insert(3, \*(Aqcat\*(Aq);
\&  $t\->insert(4, \*(Aqdog\*(Aq);
\&  my $v = $t\->find(4);
\&  my $min = $t\->min;
\&  my $max = $t\->max;
\&  $t\->delete(3);
\&  $t\->print;
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This is a perl implementation of the Red/Black tree algorithm found in the book
\&\*(L"Algorithms\*(R", by Cormen, Leiserson & Rivest (more commonly known as \*(L"\s-1CLR\*(R"\s0 or
\&\*(L"The White Book\*(R").  A Red/Black tree is a binary tree which remains \*(L"balanced\*(R"\-
that is, the longest length from root to a node is at most one more than the
shortest such length.  It is fairly efficient; no operation takes more than
O(lg(n)) time.
.PP
A Tree::RedBlack object supports the following methods:
.IP "new ()" 4
.IX Item "new ()"
Creates a new RedBlack tree object.
.IP "root ()" 4
.IX Item "root ()"
Returns the root node of the tree.  Note that this will either be undef if no
nodes have been added to the tree, or a Tree::RedBlack::Node object.  See the
Tree::RedBlack::Node manual page for details on the Node object.
.IP "cmp (&)" 4
.IX Item "cmp (&)"
Use this method to set a comparator subroutine.  The tree defaults to lexical
comparisons.  This subroutine should be just like a comparator subroutine to
sort, except that it doesn't do the \f(CW$a\fR, \f(CW$b\fR trick; the two elements to compare
will just be the first two items on the stack.
.IP "insert ($;$)" 4
.IX Item "insert ($;$)"
Adds a new node to the tree.  The first argument is the key of the node, the
second is its value.  If a node with that key already exists, its value is
replaced with the given value and the old value is returned.  Otherwise, undef
is returned.
.IP "delete ($)" 4
.IX Item "delete ($)"
The argument should be either a node object to delete or the key of a node
object to delete. \s-1WARNING\s0!!! \s-1THIS STILL HAS BUGS\s0!!!
.IP "find ($)" 4
.IX Item "find ($)"
Searches the tree to find the node with the given key.  Returns the value of
that node, or undef if a node with that key isn't found.  Note, in particular,
that you can't tell the difference between finding a node with value undef and
not finding a node at all.  If you want to determine if a node with a given key
exists, use the node method, below.
.IP "node ($)" 4
.IX Item "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.
.IP "min ()" 4
.IX Item "min ()"
Returns the node with the minimal key.
.IP "max ()" 4
.IX Item "max ()"
Returns the node with the maximal key.
.SH "AUTHOR"
.IX Header "AUTHOR"
Benjamin Holzman <bholzman@earthlink.net>
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Tree::RedBlack::Node