132 lines
4.5 KiB
Ruby
132 lines
4.5 KiB
Ruby
# binarytree.rb
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#
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# $Revision: 1.5 $ by $Author: anupamsg $
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# $Name: $
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#
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# = binarytree.rb - Binary Tree implementation
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#
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# Provides a generic tree data structure with ability to
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# store keyed node elements in the tree. The implementation
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# mixes in the Enumerable module.
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#
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# Author:: Anupam Sengupta (anupamsg@gmail.com)
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#
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# Copyright (c) 2007 Anupam Sengupta
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#
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without modification,
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# are permitted provided that the following conditions are met:
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#
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# - Redistributions of source code must retain the above copyright notice, this
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# list of conditions and the following disclaimer.
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#
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# - Redistributions in binary form must reproduce the above copyright notice, this
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# list of conditions and the following disclaimer in the documentation and/or
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# other materials provided with the distribution.
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#
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# - Neither the name of the organization nor the names of its contributors may
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# be used to endorse or promote products derived from this software without
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# specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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require 'tree'
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module Tree
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# Provides a Binary tree implementation. This tree node allows only two child
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# nodes (left and right childs). It also provides direct access to the left
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# and right children, including assignment to the same.
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class BinaryTreeNode < TreeNode
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# Adds the specified child node to the receiver node. The child node's
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# parent is set to be the receiver. The child nodes are added in the order
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# of addition, i.e., the first child added becomes the left node, and the
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# second child will be the second node.
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# If only one child is present, then this will be the left child.
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def add(child)
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raise "Already has two child nodes" if @children.size == 2
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super(child)
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end
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# Returns the left child node. Note that
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# left Child == first Child
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def leftChild
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children.first
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end
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# Returns the right child node. Note that
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# right child == last child unless there is only one child.
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# Returns nil if the right child does not exist.
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def rightChild
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children[1]
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end
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# Sets the left child. If a previous child existed, it is replaced.
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def leftChild=(child)
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@children[0] = child
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@childrenHash[child.name] = child if child # Assign the name mapping
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end
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# Sets the right child. If a previous child existed, it is replaced.
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def rightChild=(child)
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@children[1] = child
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@childrenHash[child.name] = child if child # Assign the name mapping
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end
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# Returns true if this is the left child of its parent. Always returns false
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# if this is the root node.
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def isLeftChild?
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return nil if isRoot?
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self == parent.leftChild
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end
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# Returns true if this is the right child of its parent. Always returns false
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# if this is the root node.
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def isRightChild?
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return nil if isRoot?
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self == parent.rightChild
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end
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# Swaps the left and right children with each other
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def swap_children
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tempChild = leftChild
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self.leftChild= rightChild
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self.rightChild= tempChild
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end
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end
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end
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# $Log: binarytree.rb,v $
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# Revision 1.5 2007/12/18 23:11:29 anupamsg
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# Minor documentation changes in the binarytree class.
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#
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# Revision 1.4 2007/08/30 22:08:58 anupamsg
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# Added a new swap_children method for Binary Tree. Also added minor
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# documentation and test updates.
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#
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# Revision 1.3 2007/07/21 03:24:25 anupamsg
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# Minor edits to parameter names. User visible functionality does not change.
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#
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# Revision 1.2 2007/07/18 20:15:06 anupamsg
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# Added two predicate methods in BinaryTreeNode to determine whether a node
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# is a left or a right node.
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#
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# Revision 1.1 2007/07/18 19:33:27 anupamsg
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# Added a new binary tree implementation.
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#
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