Unit 6: Algorithms

Question 1

What is an Algorithm?

Answer 1

Set of instructions for how to solve a problem/perform a task.

Question 2

What are the key techniques of Computational Thinking?

Answer 2

Abstraction
Decomposition
Algorithmic Thinking

Question 3

What is Abstraction?

Answer 3

Picking out the important parts of information and ignoring the specific details that aren’t relevant.

Question 4

What is Decomposition?

Answer 4

Breaking a complex problem into smaller problems and solving each one individually.

Question 5

What is Algorithmic Thinking?

Answer 5

A logical way of getting from the problem to the solution. If the steps you take to solve a problem follow an algorithm, they can be reused and adapted to solve similiar problems in the future.

Question 6

What is Pseudocode?

Answer 6

Not an actual programming language but shows a similiar structure and reads like one.
It is used to show an algorithm’s steps clearly without worrying about finer details (syntax) of any particular programming language.

Question 7

What does the rectangle with rounded corners represent?

Flowcharts

Answer 7

The beginning and end of the algorithm (Sometimes called terminals)

Question 8

What does the parallelogram represent?

Flowcharts

Answer 8

Inputs/Outputs of an algorithm

Question 9

What does the rectangle represent?

Flowcharts

Answer 9

General instructions, processes and calculations

Question 10

What does the diamond represent?

Flowcharts

Answer 10

Decisions - Often ‘Yes’ or ‘No’

Question 11

What does the rectangle with two lines represent?

Flowcharts

Answer 11

Sub programs

Question 12

Why are Flowcharts Used?

Answer 12

• It can show sequences, selections and iterations.
• Like pseudocode they break algorithms down into stages which can then be used by a programmer to quickly turn an algorithm into code.

Question 13

What are the two types of Searches?

Searching Algorithms is on GoodNotes

Answer 13

Linear Search
Binary Search

Searching Algorithms is on GoodNotes

Question 14

What are the Advantages and Disadvantages of Linear Searches?

Answer 14

**Advantages: **
You don’t gave to sort a list in order

**Disadvantages: **
It is the least efficient search

Question 15

What are the Advantages and Disadvantages of Binary Searches?

Answer 15

**Advantages: **
It is the quickest and most efficient search.

**Disadvantages: **
You have to sort the list before you find the item.

Question 16

What are the three sorting algorithms?

Sorting Algorithms is on GoodNotes

Answer 16

Bubble Sort
Merge Sort
Insertion Sort

Sorting Algorithms is on GoodNotes

Question 17

What are the advantages and disadvantages of Bubble sorts?

Answer 17

**Advantages: **
* It’s a simple algorithm that can be easily implemented on a computer.
* Doesn’t use much memory as all the sorting is done in the original list.
* It’s efficient to check if a list is already in order.

**Disadvantages: **
* It’s an inefficient way to sort a list.
* Because it’s inefficient it does not cope with a large amount of items

Question 18

What are the advantages and disadvantages of Merge sorts?

Answer 18

**Advantages: **
* In general it’s much quicker and more efficient than a bubble sort and insertion sort for large lists.
* It has a very consistent running time regardless of how ordered the items in the original list are.

**Disadvantages: **
* It’s slower than other algorithms for smaller lists.
* Even if the list is already sorted, it still goes through the whole splitting and merging process.
* Uses more memory than the other sorting algorithms in order to create the separate lists.

Question 19

What are the advantages and disadvantages of Insertion sorts?

Answer 19

**Advantages: **
* Copes very well with small lists.
* Very quick to add items to an already sorted list
* Very quick at checking if a list is already sorted.

**Disadvantages: **
* Like bubble sorts, doesn’t cope well with large lists.