Review: Search

1
Review Search

• Linear Search
• Binary Search
• Search demos
• http//www.cosc.canterbury.ac.nz/people/mukundan/d
  sal/appldsal.html

2
Binary Search Tree

• A binary tree where every node's left subtree has
  values less than the node's value, and every
  right subtree has values greater.
• A new node is added as a leaf.
• Check out this applet
• http//www.cs.jhu.edu/goodrich/dsa/trees/btree.ht
  ml

3
Remove node algorithm

• Find element
• If it is a leaf just delete it
• If it has one child adjust the parent to point to
  the child (thus bypassing the node)
• If it has two children
• Replace data with the smallest data of the right
  subtree
• Recursively delete the node which now needs to be
  removed

4
remove

• private BinaryNodeltAnyTypegt remove( AnyType x,
  BinaryNodeltAnyTypegt t )
• / 1/ if( t null )
• return t // Item not found do nothing
• int compareResult x.compareTo( t.element )
• / 2/ if(compareResult lt 0 )
• t.left remove( x, t.left )
• / 3/ else if(compareResult gt 0 )
• t.right remove( x, t.right )
• / 4/ else if( t.left ! null t.right ! null
  ) // Two children
• t.element findMin( t.right ).element
• t.right remove( t.element, t.right )
• /567/ else
• t ( t.left ! null ) ? t.left t.right
• return t