Data Types, Data Structures and Algorithms

Question 1

What is an array?

Answer 1

An array is an ordered, finite set of elements of a single type, where the elements are stored contiguously in memory. Each item has a common identifier and can be accessed by their index position in the array.

Question 2

What is a record?

Answer 2

A row in a file made up of fields.

Question 3

What are 2 key features of records?

Answer 3

It is mutable and can store multiple data types.

Question 4

What is 2 key feature of list?

Answer 4

It is mutable, store multiple data type.

Question 5

3 difference of list and array?

Answer 5

1.In list data is not stored next to each other in memory.
2.In list you can add data and change data while can only change data in array.
3.In list can have multiple data type but array only have 1,

Question 6

What is 3 feature of tuple?

Answer 6

1.Immutable
2.Static data type
3.Dont need to have same data type.

Question 7

What is a linked list?

Answer 7

1.A dynamic data structure
2.Each node consist of data and a pointer
3.Pointer gives location of next node.

Question 8

What is clustering?

Answer 8

Several position being filled around common collision values.

Question 9

What are all the solution of resolving collisions(3 solutions)

Answer 9

1.To repeatedly check the next available space in the hash table until an empty space is found(Open addressing)
2. Finding an alternative position of item in the hash table known as rehashing.
3.Chaining the items are in the same position but in different element of the 2D array.
4.Use a overflow table or linked list which can be searched sequently

Question 10

What is the benefit of Hash table over Linked list when we have a lot of data and incoming data?

Answer 10

1.Linked list will require each node to be checked.
2.A linked list will take longer to search as more data is added.
3.Hash tables enable direct access to the location of record.
4.It takes no longer to search as more
records are added

Question 11

What is linear probing in hash table?

Answer 11

Linear probing is a technique where the hashing function provides a start position, and a linear search is then applied from that point until the item is found.

Question 12

What is a graph?

Answer 12

A data structure containing nodes/vertices and pointer/edge.

Question 13

What are the 2 types of graph and how are they different?

Answer 13

Can be directed and undirected. Undirected means there is no specified direction but directed means point in one direction.

Question 14

What else can each edge/pointer be given?

Answer 14

Can be weighted with each edge given a value representing a relationship between nodes/vertices.

Question 15

How else can we store graphs?

Answer 15

Using an array. Known as an adjacency matrix.

Question 16

In an adjacency matrix how can we represent a link between 2 nodes if has no weight?

Answer 16

With 1 and 0s

Question 17

What is a stack known as?

Answer 17

Last in first out

Question 18

What are some operation that can be used on a stack.

Answer 18

Pop-Which pops the data at the top of the stack
Peek-Peek at the top item
Push-Push an item on a stack

Question 19

What are the 2 errors that can happen in a stack.

Answer 19

Stack overflow-When an item is pushed on a full stack
Stack underflow-When an item is popped on a empty stack

Question 20

What are application of stack?

Answer 20

Undo operation

Question 21

What do stack use and how they are normally implemented?

Answer 21

Implemented using an array and stack has pointers. A stack has a stack pointer that always point to the node at the top.

Question 22

What type of data structure is a queue.

Answer 22

First in first out

Question 23

How would we add data and remove data in a queue.

Answer 23

Using enqueue and dequeue.

Question 24

What else can we do to a queue?

Answer 24

Use a peek operation with show the first item withought deleting it.

Question 25

What else 2 type of queue is there?

Answer 25

Circular queue and priority queue.

Question 26

What pointers does a queue have?

Answer 26

A back/tail pointer pointing to the last item A front/head pointer pointing to first item

Question 27

What 2 error can happen in a queue?

Answer 27

Queue underflow-When empty queue is dequeued. Queue overflow-When full queue is enqueued,

Question 28

What is the problem with a normal Queue and how can we fix it?

Answer 28

Since front and back pointer moving in same direction as item added , the array will quickly run out of space. Can fix it using circular queue.

Question 29

How do we use a circular queue?

Answer 29

We do rear+1 mode length to get position of next item

Question 30

What is a tree?

Answer 30

Fundamental data type consisting of nodes and pointers.

Question 31

What are the 3 types of nodes in a tree?

Answer 31

Root node, Child node and Leaf node.

Question 32

How are nodes connected in trees?

Answer 32

With pointer/edges.

Question 33

What is a use of a rooted tree?

Answer 33

Storing and managing file and folder structure

Question 34

What is a binary tree?

Answer 34

Each node can only have max 2 pointer.

Question 35

What can binary tree be stored at?

Answer 35

Array and Dictionaries.

Question 36

When a Binary tree is in an array what does it contain?

Answer 36

Left pointer, Right pointer, the Data and index position

Question 37

How does a normal hash table work?

Answer 37

Convert Value into numbers, add the numbers up and mod by table size to get memory address.

Question 38

What are the 3 types of tree traversals?

Answer 38

Pre order Post order In Order

Question 39

What is In order

Answer 39

Left-node-right(Under)

Question 40

What is post order

Answer 40

left-right-root(Right)

Question 41

What is preorder -

Answer 41

Root-Left-Right(Left)