deque And Its Applications

B.Manoj - 13MX27

M.Parthiban - 13MX32

R.Sathasivam - 13MX41

G.Sivanantham - 13MX45

N.TamilArasan – 13MX49

What is deque ? A double-ended queue is an abstract data type

that generalizes a queue, for which elements can

be added to or removed from either the front or

rear.

It is also often called a head-tail linked list.

Types

Input-restricted deque

Deletion can be made from both ends , but

Insertion can be made at one end only.

Output-restricted deque

Insertion can be made at both ends , but

Deletion can be made from one end only.

Operations

pushRear() - Insert element at back

pushFront() - Insert element at front

popRear() - Remove last element

popFront() - Remove first element

isEmpty() – Checks whether the queue

is empty or not.

Example of deque Operation

Operation deque Contents Return Value

isEmpty() [] True

pushFront(‘a’) [‘a’]

pushFront(‘b’) [‘b’ , ‘a’]

pushRear(‘c’) [‘b’ , ‘a’ , ‘c’]

popFront() [‘a’ , ‘c’] ‘b’

isEmpty() [‘a’ , ‘c’] False

popRear() [‘a’] ‘c’

deque Applications

Palindrome CheckerMadam, Radar, Malayalam are some examples for palindrome

deque ApplicationsA-Steal job scheduling algorithm

– The A-Steal algorithm implements task

scheduling for several

processors(multiprocessor scheduling).

– The processor gets the first element from the

deque.

– When one of the processor completes

execution of its own threads it can steal a

thread from another processor.

– It gets the last element from the deque of

another processor and executes it.

deque Applications

Undo - Redo operation in software applications

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