# Data Structures Interview Questions with Answers 2021

## Data Structures Interview Questions with Answers 2021

What is a Data Structure? · What are linear and non-linear data Structures? DSA Interview Questions · What is data-structure? · What are various data-​structures available? · What is algorithm? ·Coding interviews are an important part of various software … Data Structures for a Coding Interview and associated common questions .

### Q1.A circular linked list can be used for

A. Stack

B. Queue

C. Both Stack & Queue

D. Neither Stack or Queue

Option C – Both Stack & Queue

### Q2.Visiting root node after visiting left and right sub-trees is called

A. In-order Traversal

B. Pre-order Traversal

C. Post-order Traveral

Option C – Post-order Traveral

### Q3.Which of the following is not possible with an array in C programming langauge −

A. Declaration

B. Definition

C. Dynamic Allocation

D . Array of strings

Option C – Dynamic Allocation

### Q4.Apriori analysis of an algorithm assumes that −

A . the algorithm has been tested before in real environment.

B . all other factors like CPU speed are constant and have no effect on implementation.

C . the algorithm needs not to be practical.

D . none of the above.

Option B – all other factors like CPU speed are constant and have no effect on implementation.

### Q5.Which if the following is/are the levels of implementation of data structure

A) Abstract level
B) Application level
C) Implementation level
D) All of the above

Option D – All of the above

### Q6.which of the following is true about the characteristics of abstract data types?i) It exports a type.ii) It exports a set of operations

A) True, False
B) False, True
C) True, True
D) False, False

Option C – True, True

### Q7.Which data structure allows deleting data elements from and inserting at rear?

A) Stacks
B) Queues
C) Dequeues
D) Binary search tree

Option B – Queues

### Q8.A ……. is a data structure that organizes data similar to a line in the supermarket, where the first one in line is the first one out.

C) Both of them
D) Neither of them

Option A – Queue linked list

### Q9.Herder node is used as sentinel in …..

A) Graphs
B) Stacks
C) Binary tree
D) Queues

Option C – Binary tree

A) Strings
B) Lists
C) Stacks
D) Graph

Option D – Graph

A) Graph
B) Trees
C) Binary tree
D) Stack

Option D – Stack

### Q12.A directed graph is ………………. if there is a path from each vertex to every other vertex in the digraph.

A) Weakly connected
B) Strongly Connected
C) Tightly Connected
D) Linearly Connected

Option B – Strongly Connected

### Q13.In general, the binary search method needs no more than ……………. comparisons.

A) [log2n]-1
B) [logn]+1
C) [log2n]
D) [log2n]+1

Option D – [log2n]+1

### Q14.A graph is a collection of nodes, called ………. And line segments called arcs or ……….. that connect pair of nodes.

A) vertices, edges
B) edges, vertices
C) vertices, paths
D) graph node, edges

Option A – vertices, edges

### Q15.There is an extra element at the head of the list called a ……….

A) Antinel
B) Sentinel

Option B – Sentinel

### Q16.A graph is said to be ……………… if the vertices can be split into two sets V1 and V2 such there are no edges between two vertices of V1 or two vertices of V2.

A) Partite
B) Bipartite
C) Rooted
D) Bisects

Option B – Bipartite

### Q17.The number of comparisons done by sequential search is ………………

A) (N/2)+1
B) (N+1)/2
C) (N-1)/2
D) (N+2)/2

Option B – (N+1)/2

### Q18.Which of the following statement is false?

A. Arrays are dense lists and static data structure.
B. Data elements in linked list need not be stored in adjacent space in memory
C. Pointers store the next data element of a list.
D. Linked lists are collection of the nodes that contain information part and next pointer.

Option C – Pointers store the next data element of a list.

### Q19.Which of the following are the operations applicable an primitive data structures?

A. create
B. destroy
C. update
D. all of the above

Option D – all of the above

### Q20.Operations on a data structure may be …..

A. creation
B. destruction
C. selection
D. all of the above

Option D – all of the above

### Q21.The logical or mathematical model of a particular organization of data is called a ………

A) Data structure
B) Data arrangement
C) Data configuration
D) Data formation

Option A – Data structure

### Q22.The simplest type of data structure is ………………

A) Multidimensional array
B) Linear array
C) Two-dimensional array
D) Three-dimensional array

Option B – Linear array

### Q23.Each node in a linked list has two pairs of ………….. and ……………….

A) Link field and information field
B) Link field and avail field
C) Avail field and information field

Option A – Link field and information field

### Q24.When does top value of the stack changes?

A) Before deletion
B) While checking underflow
C) At the time of deletion
D) After deletion

Option D – After deletion

A) Linear arrays