programming-examples/ruby/Data_Structures/b_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 BTree < MWayTree
def initialize(m)
super
@parent = nil
end
def attachSubtree(i, t)
@subtree[i] = t
t.parent = self
end
attr_accessor :parent
def insert(obj)
if empty?
if @parent.nil?
attachSubtree(0, BTree.new(m))
@key[1] = obj
attachSubtree(1, BTree.new(m))
@count = 1
else
@parent.insertUp(obj, BTree.new(m))
end
else
index = findIndex(obj)
raise ArgumentError if index != 0 and @key == obj
@subtree[index].insert(obj)
end
end
def insertUp(obj, child)
index = findIndex(obj)
if not full?
insertPair(index + 1, obj, child)
@count = @count + 1
else
extraKey, extraTree = insertPair(index+1, obj, child)
if @parent.nil?
left = BTree.new(m)
right = BTree.new(m)
left.attachLeftHalfOf(self)
right.attachRightHalfOf(self)
right.insertUp(extraKey, extraTree)
attachSubtree(0, left)
@key[1] = @key[(m + 1)/2]
attachSubtree(1, right)
@count = 1
else
@count = (m + 1)/2 - 1
right = BTree.new(m)
right.attachRightHalfOf(self)
right.insertUp(extraKey, extraTree)
@parent.insertUp(@key[(m + 1)/2], right)
end
end
end
end