MadeEasy Test Series 2018: Programming & DS - Queues

Question

Can someone explain the solution along with a picture of how the steps are taking place? 

Comments

Is it _ abc_ ?

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Yes it is _abc_ correct @minipanda

Answer 1

initially, p _ _ q r ;

where front pointer point to q and rear pointer point to p;

1. enqueue 'a'    -->    p a _ q r

2. dequeue        -->    p a _ _ r

3. enqueue 'b'    -->    p a b _ r

4. dequeue        -->    p a b  _ _

5. enqueue 'c'    -->    p a b c _  

6. dequeue        -->    _ a  b c _