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Linked List

Chapter 3

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Data Abstraction

• separates the logical properties of a data type from its implementation

• LOGICAL PROPERTIES– What are the possible values? – What operations will be needed?

• IMPLEMENTATION– How can this be done in C++?– How can data types be used?

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Data structures• A data structure is a group of data elements grouped

together under one name.• These data elements, known as members, can have

different types and different lengths. • Data structures are declared in C++ using the

following: syntax:struct structure_name {member_type1 member_name1;member_type2 member_name2;member_type3 member_name3;.} object_names;

struct product { int weight; float price;

} apple, banana, melon;

5http://www.cplusplus.com/doc/tutorial/structures/

6http://www.cplusplus.com/doc/tutorial/structures/

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Templates - Class templates• A template parameter is a special kind of parameter

that can be used to pass a type as argument:

http://www.cplusplus.com/doc/tutorial/

8http://www.cplusplus.com/doc/tutorial/

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Linked List• a linked list is a list in which the order of the

components is determined by an explicit link member in each node

• the nodes are structs--each node contains a component member and also a link member that gives the location of the next node in the list

• an external pointer (or head pointer) points to the first node in the list

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Nodes can be located anywhere inmemory

• the link member holds the memory address of the next node in the list

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Traversing a Linked List (single)

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Figure 3.1 (text book)

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Algorithm from e to h

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Insertion - Algorithm (beginning)

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Inserting a new node at the beginning of a singly linked list

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Insertion - Algorithm (end)

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Inserting a new node at the end of a singly linked list

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Deleting a node at the beginning of a singly linked list

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Deleting a node at the end of a singly linked list

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Deleting a node from a singly linked list

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Doubly Linked Lists

• An extension of a Singly Linked List• Each node has two pointer

– One pointing to the successor– One pointing to the predecessor

• They are used because they ease certain operations like the delete Element

• They are interesting for traversal as you can move in either directions

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Doubly Linked Lists (Cont.)

• Most of our structures and algorithms will be implemented with the help of Doubly Linked Lists

• Although some operations are made easier to understand they also become a bit slower due to the overhead of extra pointers

• In addition to the head a pointer called tail is also maintained

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Inserting in the Front

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Inserting in the Front (cont.)

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Inserting in the Front (cont.)

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Inserting in the Front (cont.)

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Inserting in the Front (cont.)

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Deleting element

Try your own solution

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Circular Lists

• Nodes form a ring• Each node has a successor

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Inserting a Node at the Tail of aList Circular Lists

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Inserting a Node at the Tail of aList Circular Lists (cont.)

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Inserting a Node at the Tail of aList Circular Lists (cont.)

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Inserting a Node at the Tail of aList Circular Lists (cont.)

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Skip Lists

• Linked lists require sequential scanning for a search operation

• Skip lists allow for skipping certain nodes• A skip list is an ordered linked list• A Skip List with Evenly spaced nodes of

different levels

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Figure 3.17 (self study)Note: (no need) 3.5 to 3.8