Deque Data Structure Test

1. What are the applications of dequeue?

All of the mentioned

To find the maximum of all sub arrays of size k

A-Steal job scheduling algorithm

Can be used as both stack and queue

2. Which of the following can be used to delete an element from the front end of the queue?

public Object deleteFront() throws emptyDEQException
{
	if(isEmpty())
		throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = temp.getNext();
		Object e = temp.getEle();
		temp.setNext(cur);
		size--;
		return e;
	}
}

public Object deleteFront() throws emptyDEQException
{
	if(isEmpty())
		throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = temp.getNext();
		Object e = temp.getEle();
		head.setNext(cur);
		size--;
		return e;
	}
}

public Object deleteFront() throws emptyDEQException
{
	if(isEmpty())
		throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = temp;
		Object e = temp.getEle();
		head.setNext(cur);
		size--;
		return e;
	}
}

public Object deleteFront() throws emptyDEQException
{
	if(isEmpty())
		throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = temp.getNext();
		Object e = temp.getEle();
		head.setNext(temp);
		size--;
		return e;
	}
}

3. What is the time complexity of deleting from the rear end of the dequeue implemented with a singly linked list?

O(nlogn)

O(logn)

O(n)

O(n²)

4. Select the function which performs insertion at the front end of the dequeue?

public void function(Object item)
{
	Node temp = new Node(item,null);
	if(isEmpty())
	{
		Node cur = head.getNext();
		temp.setNext(cur);
		head.setNext(temp);
	}
	else
	{
		temp.setNext(trail);
		head.setNext(temp);
	}
	size++;
}

public void function(Object item)
{
	Node temp = new Node(item,null);
	if(isEmpty())
	{
		temp.setNext(trail);
		head.setNext(trail);
	}
	else
	{
		Node cur = head.getNext();
		temp.setNext(cur);
		head.setNext(temp);
	}
	size++;
}

public void function(Object item)
{
	Node temp = new Node(item,null);
	if(isEmpty())
	{
		temp.setNext(trail);
		head.setNext(temp);
	}
	else
	{
		Node cur = head.getNext();
		temp.setNext(cur);
		head.setNext(temp);
	}
	size++;
}

public void function(Object item)
{
	Node temp = new Node(item,null);
	if(isEmpty())
	{
		Node cur = head.getNext();
		temp.setNext(cur);
		cur.setNext(temp);
	}
	else
	{
		head.setNext(trail);
		trail.setNext(temp);
	}
	size++;
}

5. What is the functionality of the following piece of code?

public void function(Object item)
{
	Node temp=new Node(item,trail);
	if(isEmpty())
	{
		head.setNext(temp);
		temp.setNext(trail);
	}
	else
	{
		Node cur=head.getNext();
		while(cur.getNext()!=trail)
		{
			cur=cur.getNext();
		}
		cur.setNext(temp);
	}
	size++;
}

Insert at the rear end of the dequeue

Insert at the front end of the dequeue

Fetch the element at the front end of the dequeue

Fetch the element at the rear end of the dequeue

6. After performing these set of operations, what does the final list look contain?

InsertFront(10);
InsertFront(20);
InsertRear(30);
DeleteFront();
InsertRear(40);
InsertRear(10);
DeleteRear();
InsertRear(15);
display();

20 30 40 10

10 30 10 15

20 30 40 15

10 30 40 15

7. Which of the following can be used to delete an element from the rear end of the queue?

public Object deleteRear() throws emptyDEQException
{
	if(isEmpty())
	throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = head;
		while(temp.getNext()!=trail)
		{
			temp = temp.getNext();
			cur = cur.getNext();
		}
		Object e = temp.getEle();
		cur.setNext(trail);
		size--;
		return e;
	}
}

public Object deleteRear() throws emptyDEQException
{
	if(isEmpty())
		throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = head;
		while(temp != trail)
		{
			temp = temp.getNext();
			cur = cur.getNext();
		}
		Object e = temp.getEle();
		cur.setNext(trail);
		size--;
		return e;
	}
}

public Object deleteRear() throws emptyDEQException
{
	if(isEmpty())
	throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = head;
		while(temp.getNext()!=trail)
		{
			temp = temp.getNext();
			cur = cur.getNext();
		}
		Object e = temp.getEle();
		temp.setNext(trail);
		size--;
		return e;
	}
}

public Object deleteRear() throws emptyDEQException
{
	if(isEmpty())
		throw new emptyDEQException("Empty");
	else
	{
		Node temp = head.getNext();
		Node cur = temp;
		while(temp.getNext() != trail)
		{
			temp = temp.getNext();
			cur = cur.getNext();
		}
		Object e = temp.getEle();
		cur.setNext(trail);
		size--;
		return e;
	}
}

8. What is a dequeue?

A queue implemented with both singly and doubly linked lists

A queue with insert/delete defined for both front and rear ends of the queue

A queue implemented with a doubly linked list

A queue with insert/delete defined for front side of the queue

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