1.4.2 - Data Structures

Question 1

What is an array?

Answer 1

An ordered, finite set of elements of a single type.

Question 2

How is a 1D array typically indexed?

Answer 2

Zero-indexed (first element is at position 0).

Question 3

What is a 2D array?

Answer 3

An array that can be visualized as a table with rows and columns.

Question 4

How do you access an element in a 2D array?

Answer 4

Specify [row, column] or [y, x] depending on convention.

Question 5

What is a 3D array?

Answer 5

An array that can be visualized as multiple 2D arrays (like a multi-page spreadsheet).

Question 6

How do you access an element in a 3D array?

Answer 6

Specify [array_number, row, column] or [z, y, x].

Question 7

What is a record?

Answer 7

A data structure made up of fields, commonly representing a row in a database.

Question 8

How are records declared?

Answer 8

Using a record structure that defines each field’s data type.

Question 9

How do you access a field in a record?

Answer 9

Using recordName.fieldName syntax.

Question 10

What is a list?

Answer 10

An ordered collection of items that can contain elements of different data types.

Question 11

How do lists differ from arrays?

Answer 11

Lists are stored non-contiguously in memory and can hold mixed data types.

Question 12

What does the isEmpty() function do for a list?

Answer 12

Checks if the list is empty.

Question 13

What does the append(value) function do?

Answer 13

Adds a new value to the end of the list.

Question 14

What does the remove(value) function do?

Answer 14

Removes the first occurrence of the specified value.

Question 15

What does the search(value) function do?

Answer 15

Searches for a value in the list and returns a boolean.

Question 16

What does the length() function do?

Answer 16

Returns the number of items in the list.

Question 17

What does the index(value) function do?

Answer 17

Returns the position of the first occurrence of the value.

Question 18

What does the insert(position, value) function do?

Answer 18

Inserts a value at the specified position in the list.

Question 19

What does the pop() function do?

Answer 19

Removes and returns the last value in the list.

Question 20

What does the pop(position) function do?

Answer 20

Removes and returns the value at the specified position.

Question 21

What is a tuple?

Answer 21

An ordered, immutable set of values of any type.

Question 22

How are tuples different from lists?

Answer 22

Tuples are immutable (cannot be changed after creation).

Question 23

How are tuples initialized?

Answer 23

Using regular parentheses () instead of square brackets [].

Question 24

What is a linked list?

Answer 24

A dynamic data structure where each node contains data and a pointer to the next node.

Question 25

What are the components of a linked list node?

Answer 25

Data field and pointer/reference field.

Question 26

What pointers are maintained in a linked list?

Answer 26

Start pointer (first node) and NextFree pointer (next available space).

Question 27

How do you traverse a linked list?

Answer 27

Start at the Start pointer and follow pointers until reaching a null pointer.

Question 28

How are values added to a linked list?

Answer 28

Update pointers to insert the new node in the sequence.

Question 29

How are values removed from a linked list?

Answer 29

Update pointers to bypass the node to be removed.

Question 30

What is a graph?

Answer 30

A set of vertices/nodes connected by edges/arcs.

Question 31

What is a directed graph?

Answer 31

Edges can only be traversed in one direction.

Question 32

What is an undirected graph?

Answer 32

Edges can be traversed in both directions.

Question 33

What is a weighted graph?

Answer 33

Edges have associated costs/weights.

Question 34

What is an adjacency matrix?

Answer 34

A 2D array representing which vertices are connected.

Question 35

What is an adjacency list?

Answer 35

A collection of lists showing each vertex's connections.

Question 36

What is a stack?

Answer 36

A LIFO (Last In First Out) data structure.

Question 37

What are common stack operations?

Answer 37

push(value), pop(), peek(), isEmpty(), isFull(), size()

Question 38

What does push(value) do?

Answer 38

Adds a value to the top of the stack.

Question 39

What does pop() do?

Answer 39

Removes and returns the top value from the stack.

Question 40

What does peek() do?

Answer 40

Returns the top value without removing it.

Question 41

What is a queue?

Answer 41

A FIFO (First In First Out) data structure.

Question 42

What are common queue operations?

Answer 42

enQueue(value), deQueue(), isEmpty(), isFull()

Question 43

What does enQueue(value) do?

Answer 43

Adds a value to the end of the queue.

Question 44

What does deQueue() do?

Answer 44

Removes and returns the value from the front of the queue.

Question 45

What is a linear queue?

Answer 45

A queue implemented as an array with front and rear pointers.

Question 46

What is a circular queue?

Answer 46

A queue where the rear pointer can wrap around to the front when full.

Question 47

What is a tree?

Answer 47

A connected graph with a root node and hierarchical structure.

Question 48

What is a binary tree?

Answer 48

A tree where each node has at most two children.

Question 49

What is pre-order traversal?

Answer 49

Root node, left subtree, right subtree.

Question 50

What is in-order traversal?

Answer 50

Left subtree, root node, right subtree.

Question 51

What is post-order traversal?

Answer 51

Left subtree, right subtree, root node.

Question 52

What is a hash table?

Answer 52

An array coupled with a hash function that maps keys to indices.

Question 53

What is a hash function?

Answer 53

A function that takes a key and returns an index in the hash table.

Question 54

What is a collision in hashing?

Answer 54

When two different keys produce the same hash value.

Question 55

What is collision resolution?

Answer 55

Handling collisions, often by placing the item in the next available location.