Data Structures Quiz

What is the functionality of the following piece of code? public void display() { if(size == 0) System.out.println("underflow"); else { Node current = first; while(current != null) { System.out.println(current.getEle()); current = current.getNext(); } } }

• display the list

• reverse the list

• reverse the list excluding top-of-the-stack-element

• display the list excluding top-of-the-stack-element

Consider the following doubly linked list: head-1-2-3-4-5-tail. What will be the list after performing the given sequence of operations? Node temp = new Node(6,head,head.getNext()); Node temp1 = new Node(0,tail.getPrev(),tail); head.setNext(temp); temp.getNext().setPrev(temp); tail.setPrev(temp1); temp1.getPrev().setNext(temp1);

• head-0-1-2-3-4-5-6-tail

• head-1-2-3-4-5-6-tail

• head-6-1-2-3-4-5-0-tail

• head-0-1-2-3-4-5-tail

Which of the following is false about a doubly linked list?

• We can navigate in both the directions

• It requires more space than a singly linked list

• The insertion and deletion of a node take a bit longer

• Implementing a doubly linked list is easier than singly linked list

If the elements “A”, “B”, “C” and “D” are placed in a queue and are deleted one at a time, in what order will they be removed?

• ABCD

• DCBA

• DCAB

• ABDC

A normal queue, if implemented using an array of size MAX_SIZE, gets full when?

• Rear = MAX_SIZE – 1

• Front = (rear + 1)mod MAX_SIZE

• Front = rear + 1

• Rear = front

What is the result of the following postfix expression? ab*cd*+ where a=2,b=2,c=3,d=4.

• 16

• 12

• 14

• 10

Consider the stack | 5 | | 4 | | 3 | | 2 |. At this point, ‘*’ is encountered. What has to be done?

• 5*4=20 is pushed into the stack

• * is pushed into the stack

• 2*3=6 is pushed into the stack

• * is ignored

Which of the following statements are not correct with respect to Singly Linked List(SLL) and Doubly Linked List(DLL)?

• Complexity of Insertion and Deletion at known position is O(n) in SLL and O(1) in DLL

• SLL uses lesser memory per node than DLL

• DLL has more searching power than SLL

• Number of node fields in SLL is more than DLL

What does the following function do? public Object some_func()throws emptyStackException { if(isEmpty()) throw new emptyStackException("underflow"); return first.getEle(); }

• pop

• delete the top-of-the-stack element

• retrieve the top-of-the-stack element

• push operation

Minimum number of queues to implement stack is ___________

• 3

• 4

• 1

• 2