268 Data Structure Lecture 3

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268 Data Structure Lecture 3

• Soundararajan Ezekiel
• Department of Computer Science
• Ohio Northern University
• ADA, OHIO 45810

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Announcement

• Written Assignment 1
• Out today
• Quiz 1 today( Last 10- 15 Min)
• This Friday Lab Problems
• Out today

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Review Fundamental ADT(Abstract Data Type)

• Collection
• boolean isEmpty
• int size
• Enumeration elements
• Bag Simplest type of collection
• addElement
• containsElement
• findElement
• removeElement

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Set

• Same as Mathematical Set--
• Every element is unique--
• It allow no duplication
• addElement adds elements to the set if it is not
  already present
• unionWith Forms union of current set with
  argument set--Argument set is not modified

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Continue

• intersectWith Forms intersection of the current
  set with argument set-Argument set is not
  modified
• differenceWith form difference between current
  set and argument set-- argument set is not
  modified
• subsetOfreturns True if the members of current
  set is also members of argument set
• False Otherwise

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Sorted

• One of the most frequently performed computing
  task--studied intensively-- many algorithms have
  been devised--
• given the set of elements, the sorting problem is
  to arrange the elements from smallest to largest

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Types of Sort

• Insertion sort-
• Bubble sort-
• selection sort--
• the cost of exchange of sort-
• shell sort--
• quick sort--
• mergesort--
• heapsort--
• binsort--
• radix sort--

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Comparable

• int compare(Object RHS)
• compare this object with RHS for order
• return negative(-1) if this object is less than
  RHS
• return Zero if equal
• return Positive(1) if this object is greater
  than RHS
• throw ClassCastException if it not comparable

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Comparator

• int compare(Object RHS, Object RHS)
• compares its two arguments for order, using the
  same rules as compareTo
• Most useful when the natural ordering is not
  exactly what is needed
• example sort the string by their string

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Stack

• A stack is a container of objects that are
  inserted and removed according to the last-in
  first-out(LIFO)principle
• Objects can be inserted into a stack at any time
  BUT the most recently inserted (that is
  last)object can be removed at any time.
• The name stack is derived from the metaphor of
  a stack of plates in a spring-loaded , cafeteria
  plate dispensor

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Example1 Stack

• Internet Web Browsers store the addresses of
  recently visited sites on a stack. ---Each time a
  user visits a new site, that sites address is
  pushed on to the stack of addressed. The browser
  then allow the user to pop back to previously
  visited sites using the back button

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Example 2

• Text Editors usually provide an undo mechanism
  that cancels recent operations and reverts to
  former states of a document. This undo operation
  can be accomplished by keeping text changes in a
  stack

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Stack supports

• push
• pop
• size
• isEmpty
• top

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Queue

• Another fundamental ADT is queue
• It is a close cousin of Stack
• is a container of object that are inserted and
  removed according to the first-in first-out
  (FIFO) principle
• that is elements can be inserted at any time, but
  only the element that has been in the queue the
  longest can be removed at any time
• enter queue at rear and are removed from the
  front
• addLast---- getFirst -- nosuchElementException

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Deque

• Cobines the feature of Stack and Queue
• Adding and Removing Elements from both sides

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FindMin FindNth

• Add new elements to collection
• find and remove the smallest( min) value of the
  collection
• FindNth-- provide ability to find Nth smallest
  value in a collection

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Indexed Collection and Sorting Algorithm

• able to access in a sequence, from beginning to
  end
• Objects are indexed using integer value index
• Like arrays

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Map

• Map a map is used to store a collection of
  entries that consists of keys and their values
• the Map maps keys to values
• keys must be unique, but several keys can map to
  the same values
• these values need not to be unique
• the map is implemented by Hashmap and Treemap

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Matrix

• 2-dim structure
• setSize
• numberRows
• numberColumns
• elementAt
• setElementAt