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