JAVA & Linked List Implementation

1. JAVA & Linked List Implementation Group VIPresented byRegulapati Venkata Ramana Rao

2. Objective • Purpose • Types of linked list • Organization • Different operations • Bio-Oh of each operation • Case study

3. Introduction • Is the linear data structure represented by nodes • Is an alternative to the contiguous array implementation • It Consists of collection of connected , dynamically allocated Nodes • Each node will have at least two elements • Element itself • The link to the next node in the list Link to next node Element 11 12

4. Introduction • Linked List Node Representation Class ListNode { Object element; ListNode nextNode; }

5. Introduction • Why Linked List ? • Inserting or deleting of an item into/from list is easy, where as it requires extensive data movement if we use arrays • Insertion Into Sorted Array • Insert 4 into above array • Increase the array size • Locate the position of 4. Big-oh is O(N) • Move the elements by one position. Big-oh is O(N) • So Big-Oh is O(N2) 1 2 3 5 6 7

6. Introduction • Array After Inserting • Linked List Implementation • Inserting Element 4 • Create new node with element 4 ListNode tmp = new ListNode(); tmp.element = 4; • Search the position of element Big-Oh(N) 1 2 3 4 5 6 7 header 1 2 5 6 tmp 4

7. Introduction • Insertion… • Point the new node link to the node after the new node temp.next = current.next; • Point the previous node link to new node current.next = tmp; • Big-Oh is O(N) Note: So Linked list is efficient in this case current 1 2 5 6 tmp 4

8. Types • Linked Lists are 3 types Single Linked List • Consists of data element and reference to the next Node in the Linked list • First node is accessed by reference (Header Node) • Last node is set to NULL Head 11 12 13

9. Types • Double Linked List • Consists of nodes with two link members one points to the previous and other to the next node • Maximizes the needs of list traversals • Compared to the Singled list inserting and deleting nodes is a bit slower as both the links has to be updated • It requires the extra storage space for the second link Head 11 11 11

10. Types • Circular Linked list • Similar to the doubly linked list, but the last node link points to the first node instead of null • Useful in algorithms where there is no particular first or last item • Advantage is we can make head to point any node without destroying the list • Operations are similar to single linked list except identifying the last node in the list. To find the last node compare the last node to head node (i.e you have found the last node if its link points to the same node that the head points)

11. Types • Circularly Linked List Representation first 11 12 13

12. Header & Trailer Nodes • Header Node: A placeholder node at the beginning of list, used to simplify list processing.It doesn’t hold any data but satisfies that the every node has a previous node. • Trailer Node: A placeholder node at the end of list, used to simplify list processing

13. Single LinkedList Operations • Insertion of node Consider 3 cases of insertion • Node is first node in the linked list • Node is an inner node • Node is last node • Deleting specific node • Printing/Traversing Liked List • Find specific node • Find Length of Linked List

14. Implementation • All the above mentioned operations are implemented on a sorted singly linked list in the following example • The implementation has these classes • List.java … This is the interface • LinkedList.java … Implementation for the methods declared in interface • Node.java … This is actual Node in Linked list and also has Accessor / Mutator methods • TestLinkedList.java … Test client program

15. List.java Interface

16. Node.java

17. Node.java

18. LinkedList.java //This class Implements the List interface

19. LinkedList.java

20. LinkedList.java

21. LinkedList.java

22. LinkedList.java

23. LinkedList.java

24. LinkedList.java

25. InvalidElementException.java

26. ClientLinkedList.java

27. ClientLinkedList.java

28. ClientLinkedList.java