Doubly linked lists provide the advantage of finding the predecessor and successor in constant time, instead of in linear time for singly-linked lists. The name “doubly linked list” implies that there are two links per node: one to the previous and one to the next element in the sequence. It is always better to get assistance from a reputed tutor or get study material like Doubly Linked List Questions and Answers containing questions and answers. These Doubly Linked List Questions And Answers will help you prepare for any exam including GATE, GRE, IES, PSC, UGC NET, DOEACC Exams at all levels – you just have to practice regularly.

## Doubly Linked List Questions And Answers

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

a) We can navigate in both the directions

b) It requires more space than a singly linked list

c) The insertion and deletion of a node take a bit longer

d) Implementing a doubly linked list is easier than singly linked list

**Answer: **implementing a doubly linked list is easier than singly linked list

**2. What is a memory efficient double linked list?**

a) Each node has only one pointer to traverse the list back and forth

b) The list has breakpoints for faster traversal

c) An auxiliary singly linked list acts as a helper list to traverse through the doubly linked list

d) A doubly linked list that uses bitwise AND operator for storing addresses

**Answer: **Each node has only one pointer to traverse the list back and forth

**3. What is a memory efficient double linked list?**

a) Each node has only one pointer to traverse the list back and forth

b) The list has breakpoints for faster traversal

c) An auxiliary singly linked list acts as a helper list to traverse through the doubly linked list

d) A doubly linked list that uses bitwise AND operator for storing addresses

**Answer: **Each node has only one pointer to traverse the list back and forth

**4. How do you calculate the pointer difference in a memory efficient double linked list?**

a) head xor tail

b) pointer to previous node xor pointer to next node

c) pointer to previous node – pointer to next node

d) pointer to next node – pointer to previous node

**Answer: **pointer to previous node xor pointer to next node

**5. 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());
head.setNext(temp);
temp.getNext().setPrev(temp);
Node temp1 = tail.getPrev();
tail.setPrev(temp1.getPrev());
temp1.getPrev().setNext(tail);
```

a) head-6-1-2-3-4-5-tail

b) head-6-1-2-3-4-tail

c) head-1-2-3-4-5-6-tail

d) head-1-2-3-4-5-tail

**Answer: **head-6-1-2-3-4-tail

### More Questions on Abstract Data Types (Data Structure)

### Some FAQs and Answers on Doubly Linked List

**What is doubly linked list with example?**

**Answer:** In computer science, a doubly linked list is a linked data structure that consists of a set of sequentially linked records called nodes. Each node contains three fields: two link fields (references to the previous and to the next node in the sequence of nodes) and one data field.

**What is doubly linked list used for?**

**Answer:** It is used in the navigation systems where front and back navigation is required. It is used by the browser to implement backward and forward navigation of visited web pages that is a back and forward button. It is also used to represent a classic game deck of cards.

**What is a doubly linked list in C?**

**Answer:** Doubly linked list is a complex type of linked list in which a node contains a pointer to the previous as well as the next node in the sequence. In C, structure of a node in doubly linked list can be given as : struct node.

**What is doubly ended linked list?**

**Answer:** In a double-ended linked list, each node has just one pointer which points to its next node. Its difference from the single-ended linked list is that instead of just one “head” node, it contains two pointers of this kind (“first” and “last”), so someone is able to insert elements to list from both ends of it.

**What is the difference between Linked List and doubly linked list?**

**Answer:** Singly linked list allows traversal elements only in one way. Doubly linked list allows element two way traversal. As singly linked list store pointer of only one node so consumes lesser memory. On other hand Doubly linked list uses more memory per node(two pointers).