SLR04 - Data Structure

Question 1

What is a data structure?

Answer 1

A way of organising and storing data in a computer so it can be accessed and modified efficiently.

Question 2

What is an array?

Answer 2

A static data structure that stores data contiguously in memory and holds one data type.

Question 3

Difference between array and list?

Answer 3

Arrays are static and store one data type; lists are dynamic and can store multiple data types.

Question 4

Difference between tuple and list?

Answer 4

Tuple is immutable and fixed-size. list is mutable and changeable.

Question 5

Why are arrays called static?

Answer 5

Because their size is fixed at the time of creation and cannot be changed later.

Question 6

What is a binary file?

Answer 6

A non-text file storing data in binary form, often with mixed data types.

Question 7

How is a real number stored differently in a binary file?

Answer 7

Stored in compact binary form instead of text, using fewer bytes.

Question 8

What is a static data structure?

Answer 8

A structure with a fixed size where memory allocation doesn’t change during program runtime.

Question 9

One benefit and drawback of static structures?

Answer 9

Benefit: Easier to program. Drawback: Inefficient use of memory.

Question 10

What is a dynamic data structure?

Answer 10

A structure that can grow and shrink during runtime.

Question 11

One benefit and drawback of dynamic structures?

Answer 11

Benefit: Efficient memory use. Drawback: Harder to program.

Question 12

What is a stack?

Answer 12

A LIFO (Last-In-First-Out) data structure.

Question 13

What operations are used on a stack?

Answer 13

Push, Pop, Peek.

Question 14

What is stack overflow and underflow?

Answer 14

Overflow: Pushing to full stack. Underflow: Popping from empty stack.

Question 15

What does the stack pointer do?

Answer 15

Points to the top item of the stack.

Question 16

What is a queue?

Answer 16

A FIFO (First-In-First-Out) data structure.

Question 17

What operations are used on a queue?

Answer 17

Enqueue, Dequeue, Peek.

Question 18

What is stack overflow and underflow?

Answer 18

Overflow: Pushing to full stack. Underflow: Popping from empty stack.

Question 19

What does the stack pointer do?

Answer 19

Points to the top item of the stack.

Question 20

What is a queue?

Answer 20

A FIFO (First-In-First-Out) data structure.

Question 21

What operations are used on a queue?

Answer 21

Enqueue, Dequeue, Peek.

Question 22

What is queue overflow and underflow?

Answer 22

Overflow: Enqueue to full queue. Underflow: Dequeue from empty queue.

Question 23

What are front and back pointers in a queue?

Answer 23

Front: Points to the item to dequeue. Back: Points to where to enqueue.

Question 24

What problem does a circular queue solve?

Answer 24

Prevents unused space when back reaches the end of the array by looping around.

Question 25

Steps to push to a stack?

Answer 25

Check overflow → Increment pointer → Insert item.

Question 26

Steps to pop from a stack?

Answer 26

Check underflow → Output item → Decrement pointer.

Question 27

Steps to enqueue to a queue?

Answer 27

Check overflow → Increment back pointer → Insert item.

Question 28

Steps to dequeue from a queue?

Answer 28

Check underflow → Output item → Increment front pointer.

Question 29

What is a graph?

Answer 29

A structure with nodes and edges. Edges may be directed or undirected.

Question 30

What is a directed vs undirected graph?

Answer 30

Directed: edges point one way. Undirected: edges go both ways.

Question 31

What is a weighted graph?

Answer 31

A graph where each edge has a value (e.g., distance, cost).

Question 32

What is an adjacency matrix?

Answer 32

2D array representing graph edges between nodes.

Question 33

What is an adjacency list?

Answer 33

Dictionary mapping nodes to a list of connected nodes.

Question 34

When is adjacency list better than matrix?

Answer 34

When the graph is sparse (fewer connections).

Question 35

What is a tree?

Answer 35

A connected, undirected graph with no cycles.

Question 36

What is a rooted tree?

Answer 36

A tree with one root node at the top.

Question 37

What is a binary tree?

Answer 37

A tree where each node has up to 2 children (left, right).

Question 38

How are binary trees stored?

Answer 38

As arrays or dictionaries.

Question 39

What is a hash table?

Answer 39

A data structure that maps keys to values using a hash function.

Question 40

What is a hash function?

Answer 40

A function that calculates the index to store or find data.

Question 41

What is a collision in hashing?

Answer 41

When two keys hash to the same index.

Question 42

What is open addressing?

Answer 42

Finding next empty space when collision occurs.

Question 43

What is linear probing?

Answer 43

Searching sequentially for next available slot.

Question 44

What is rehashing?

Answer 44

Finding a new position for a key when collision occurs.

Question 45

Steps to add to a hash table?

Answer 45

Hash → If empty, insert → Else check overflow table → Insert when space found.

Question 46

Steps to delete from a hash table?

Answer 46

Hash → If match, delete → Else search overflow table → Delete when found.

Question 47

Steps to search a hash table?

Answer 47

Hash → Check value → If not match, check overflow table → Return value or 'Not Found'.

Question 48

What is a dictionary?

Answer 48

An abstract data structure storing key-value pairs.

Question 49

How is a dictionary accessed?

Answer 49

Using the key to retrieve the associated value.

Question 50

What is a vector?

Answer 50

A series of numbers representing data like position, velocity, or force.