programming-examples/ruby/Data_Structures/binary_search_tree.rb

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2019-11-15 12:59:38 +01:00
# This file contains the Ruby code from book of
# "Data Structures and Algorithms
# with Object-Oriented Design Patterns in Ruby"
# by Bruno R. Preiss.
#
# Copyright (c) 2004 by Bruno R. Preiss, P.Eng. All rights reserved.
class BinarySearchTree < BinaryTree
include SearchTreeMethods
def initialize(*args)
super
end
def find(obj)
return nil if empty?
diff = obj <=> @key
if diff == 0
return @key
elsif diff < 0
return @left.find(obj)
elsif diff > 0
return @right.find(obj)
end
end
def min
if empty?
return nil
elsif @left.empty?
return @key
else
return @left.min
end
end
def insert(obj)
if empty?
attachKey(obj)
else
diff = obj <=> @key
if diff == 0
raise ArgumentError
elsif diff < 0
@left.insert(obj)
elsif diff > 0
@right.insert(obj)
end
end
balance
end
def attachKey(obj)
raise StateError if not empty?
@key = obj
@left = BinarySearchTree.new
@right = BinarySearchTree.new
end
def balance
end
def withdraw(obj)
raise ArgumentError if empty?
diff = obj <=> @key
if diff == 0
if not @left.empty?
max = @left.max
@key = max
@left.withdraw(max)
elsif not @right.empty?
min = @right.min
@key = min
@right.withdraw(min)
else
detachKey
end
elsif diff < 0
@left.withdraw(obj)
elsif diff > 0
@right.withdraw(obj)
end
balance
end
end