DS Foundations: 18 MCQs with answers

A method of organizing and storing data for efficient use

A data structure is a method of organizing and storing data so that it can be used efficiently for processing, retrieval, updating, and deletion.

Integer

Primitive data structures are basic types provided by programming languages, such as int, char, float, and bool. Arrays, stacks, and trees are non-primitive.

Stack

The Undo operation follows Last-In-First-Out (LIFO) order, which is exactly how a stack works.

In a sequential manner

Linear data structures arrange elements one after another, with each element having a unique predecessor and successor (except first and last).

Tree

Trees are non-linear because elements are arranged hierarchically, not sequentially. Arrays, queues, and linked lists are linear.

Tree

A family tree has hierarchical relationships, which is exactly what a tree data structure represents.

Stack

Stacks follow LIFO, where the last element added is the first one removed.

Stack

Browser history uses a stack because the last visited page is on top and is accessed first (LIFO).

False

Arrays are non-primitive because they organize multiple values, even though they store primitive values.

False

Dynamic data structures allocate memory at runtime, allowing flexible size changes.

Static structures have fixed size, dynamic can change at runtime

Static data structures have a fixed size allocated at compile time, while dynamic data structures can grow or shrink at runtime.

base address + (i × size of element)

Array elements are stored contiguously, so the address of arr[i] is base address plus i times the size of each element.

A logical description of data and operations without implementation details

An ADT defines what operations can be performed on data but hides the implementation details, like a remote control hides internal circuits.

Priority Queue

Priority queues allow tasks with higher priority to be executed first, which is essential for CPU scheduling.

Linked List

Linked lists allocate memory at runtime, allowing them to grow or shrink as needed, making them dynamic.

Nodes are entities, edges are relationships

In a graph, nodes represent entities (like locations or users), and edges represent relationships (like roads or friendships).

Easier insertion and deletion

Linked lists allow easy insertion and deletion because they use pointers, whereas arrays require shifting elements.

O(V^2)

An adjacency matrix stores a 2D array of size V x V, so space complexity is O(V^2).