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Write code to implement a queue using arrays in which insertions and deletions can be made from either end of the structure (such a queue is called deque). Your code should be able to perform the following operations (i) Insert element in a deque (ii) Remove element from a deque (iii) Check if deque is empty (iv) Check if it is full (v) Initialize it |
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Answer» Here there are 4 operations 1. q insert front 2. q insert rear 3. q delete front 4. q delete rear when front = rear = -1, queue is empty when (rear+1) mod size of queue = front queue is full. Here the queue is to be used circularly. (1) q insert front if (front==rear==-1) then front=rear=0 q (front)=item else if(rear+1)mod sizeof q=front q is full, insertion not possible else front = (front + sizeof q-1) mod sizeof q (2) q insert rear if (front==rear==-1) front=rear=0 q(rear)=item else if (rear+1) mod sizeof queue + front queue is full, insertion not possible else rear = (rear+1) mode sizeof queue q(rear) = item (3) q delete front if (front==rear==-1) queue is empty else if (front==rear) k = q(front), front = rear= -1 return(k) else k=q(front) front = (front+1) mod sizeof queue return (k) (4) q delete rear if (front==rear==-1) queue is empty else if (front==rear) k = q(rear), front=rear=-1 return(k) else k=q(rear) rear = (rear +size of queue -1) mod sizeof q return (k) |
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