Initial commit
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Michael Reber
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BinarySearchTree.cpp - Implementation for binary search tree
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#include "BinarySearchTree.h"
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#include <iostream.h>
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/**
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* Implements an unbalanced binary search tree.
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* Note that all "matching" is based on the < method.
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*/
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/**
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* Construct the tree.
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*/
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template <class Comparable>
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BinarySearchTree<Comparable>::BinarySearchTree( const Comparable & notFound ) :
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root( NULL ), ITEM_NOT_FOUND( notFound )
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{
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}
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/**
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* Copy constructor.
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*/
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template <class Comparable>
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BinarySearchTree<Comparable>::
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BinarySearchTree( const BinarySearchTree<Comparable> & rhs ) :
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root( NULL ), ITEM_NOT_FOUND( rhs.ITEM_NOT_FOUND )
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{
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*this = rhs;
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}
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/**
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* Destructor for the tree.
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*/
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template <class Comparable>
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BinarySearchTree<Comparable>::~BinarySearchTree( )
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{
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makeEmpty( );
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}
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/**
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* Insert x into the tree; duplicates are ignored.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::insert( const Comparable & x )
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{
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insert( x, root );
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}
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/**
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* Remove x from the tree. Nothing is done if x is not found.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::remove( const Comparable & x )
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{
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remove( x, root );
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}
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/**
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* Find the smallest item in the tree.
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* Return smallest item or ITEM_NOT_FOUND if empty.
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*/
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template <class Comparable>
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const Comparable & BinarySearchTree<Comparable>::findMin( ) const
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{
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return elementAt( findMin( root ) );
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}
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/**
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* Find the largest item in the tree.
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* Return the largest item of ITEM_NOT_FOUND if empty.
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*/
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template <class Comparable>
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const Comparable & BinarySearchTree<Comparable>::findMax( ) const
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{
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return elementAt( findMax( root ) );
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}
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/**
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* Find item x in the tree.
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* Return the matching item or ITEM_NOT_FOUND if not found.
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*/
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template <class Comparable>
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const Comparable & BinarySearchTree<Comparable>::
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find( const Comparable & x ) const
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{
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return elementAt( find( x, root ) );
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}
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/**
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* Make the tree logically empty.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::makeEmpty( )
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{
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makeEmpty( root );
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}
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/**
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* Test if the tree is logically empty.
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* Return true if empty, false otherwise.
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*/
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template <class Comparable>
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bool BinarySearchTree<Comparable>::isEmpty( ) const
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{
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return root == NULL;
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}
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/**
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* Print the tree contents in sorted order.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::printTree( ) const
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{
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if( isEmpty( ) )
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cout << "Empty tree" << endl;
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else
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printTree( root );
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}
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/**
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* Deep copy.
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*/
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template <class Comparable>
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const BinarySearchTree<Comparable> &
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BinarySearchTree<Comparable>::
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operator=( const BinarySearchTree<Comparable> & rhs )
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{
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if( this != &rhs )
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{
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makeEmpty( );
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root = clone( rhs.root );
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}
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return *this;
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}
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/**
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* Internal method to get element field in node t.
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* Return the element field or ITEM_NOT_FOUND if t is NULL.
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*/
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template <class Comparable>
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const Comparable & BinarySearchTree<Comparable>::
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elementAt( BinaryNode<Comparable> *t ) const
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{
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if( t == NULL )
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return ITEM_NOT_FOUND;
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else
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return t->element;
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}
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/**
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* Internal method to insert into a subtree.
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* x is the item to insert.
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* t is the node that roots the tree.
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* Set the new root.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::
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insert( const Comparable & x, BinaryNode<Comparable> * & t ) const
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{
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if( t == NULL )
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t = new BinaryNode<Comparable>( x, NULL, NULL );
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else if( x < t->element )
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insert( x, t->left );
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else if( t->element < x )
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insert( x, t->right );
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else
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; // Duplicate; do nothing
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}
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/**
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* Internal method to remove from a subtree.
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* x is the item to remove.
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* t is the node that roots the tree.
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* Set the new root.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::
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remove( const Comparable & x, BinaryNode<Comparable> * & t ) const
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{
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if( t == NULL )
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return; // Item not found; do nothing
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if( x < t->element )
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remove( x, t->left );
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else if( t->element < x )
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remove( x, t->right );
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else if( t->left != NULL && t->right != NULL ) // Two children
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{
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t->element = findMin( t->right )->element;
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remove( t->element, t->right );
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}
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else
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{
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BinaryNode<Comparable> *oldNode = t;
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t = ( t->left != NULL ) ? t->left : t->right;
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delete oldNode;
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}
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}
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/**
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* Internal method to find the smallest item in a subtree t.
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* Return node containing the smallest item.
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*/
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template <class Comparable>
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BinaryNode<Comparable> *
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BinarySearchTree<Comparable>::findMin( BinaryNode<Comparable> *t ) const
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{
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if( t == NULL )
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return NULL;
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if( t->left == NULL )
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return t;
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return findMin( t->left );
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}
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/**
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* Internal method to find the largest item in a subtree t.
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* Return node containing the largest item.
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*/
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template <class Comparable>
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BinaryNode<Comparable> *
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BinarySearchTree<Comparable>::findMax( BinaryNode<Comparable> *t ) const
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{
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if( t != NULL )
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while( t->right != NULL )
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t = t->right;
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return t;
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}
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/**
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* Internal method to find an item in a subtree.
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* x is item to search for.
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* t is the node that roots the tree.
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* Return node containing the matched item.
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*/
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template <class Comparable>
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BinaryNode<Comparable> *
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BinarySearchTree<Comparable>::
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find( const Comparable & x, BinaryNode<Comparable> *t ) const
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{
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if( t == NULL )
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return NULL;
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else if( x < t->element )
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return find( x, t->left );
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else if( t->element < x )
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return find( x, t->right );
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else
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return t; // Match
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}
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/****** NONRECURSIVE VERSION*************************
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template <class Comparable>
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BinaryNode<Comparable> *
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BinarySearchTree<Comparable>::
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find( const Comparable & x, BinaryNode<Comparable> *t ) const
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{
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while( t != NULL )
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if( x < t->element )
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t = t->left;
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else if( t->element < x )
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t = t->right;
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else
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return t; // Match
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return NULL; // No match
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}
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*****************************************************/
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/**
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* Internal method to make subtree empty.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::
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makeEmpty( BinaryNode<Comparable> * & t ) const
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{
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if( t != NULL )
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{
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makeEmpty( t->left );
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makeEmpty( t->right );
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delete t;
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}
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t = NULL;
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}
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/**
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* Internal method to print a subtree rooted at t in sorted order.
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*/
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template <class Comparable>
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void BinarySearchTree<Comparable>::printTree( BinaryNode<Comparable> *t ) const
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{
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if( t != NULL )
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{
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printTree( t->left );
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cout << t->element << endl;
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printTree( t->right );
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}
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}
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/**
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* Internal method to clone subtree.
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*/
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template <class Comparable>
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BinaryNode<Comparable> *
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BinarySearchTree<Comparable>::clone( BinaryNode<Comparable> * t ) const
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{
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if( t == NULL )
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return NULL;
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else
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return new BinaryNode<Comparable>( t->element, clone( t->left ), clone( t->right ) );
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}
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