2.1 Algorithms

Question 1

Computational Thinking

Answer 1

steps taken to find a solution to a complex problem. It involves Decomposition, Abstraction and Algorithmic Thinking.

Question 2

Decomposition:

Answer 2

Decomposition is breaking down a complex problem down into smaller problems and solving each one individually.

Question 3

Abstraction:

Answer 3

picking out the important bits of information from the problem and ignoring the specific details that don’t matter.

Question 4

Algorithmic Thinking:

Answer 4

logical
way of getting from a problem to a solution. If the steps you take follow an algorithm, this can be used again in the future.

Question 5

Pseudocode:

Answer 5

not an actual programming language, it shows the steps of the algorithm without the need to follow syntax. It can easily be followed by a coder.

Question 6

Flowcharts:

Answer 6

Algorithms can be shown using a flowchart. Flowcharts use different shaped boxes for different commands.

Question 7

Search algorithm:

Answer 7

Computers follow a search algorithm to find items in a list e.g. searching a shopping website, searching for appointments at a doctor’s surgery.

Question 8

Binary search:

Answer 8

Binary Search looks for items in an ordered list. The list can contain letters, numbers or alphanumeric characters

Question 9

Linear search:

Answer 9

can be used on an
unordered list. This type of search checks each item in turn and stops when it finds the item or reaches the end of the list. Starts at start

Question 10

Sorting algorithm:

Answer 10

follow a sorting algorithm to sort items in a list
e.g. sorting a list of names in Excel, shopping website – sorting a list from lowest to highest price.

Question 11

Bubble sort:

Answer 11

Compares pairs of items. Very simple but can take a long time to sort large lists

Question 12

Merge sort:

Answer 12

splits the list apart then merges if back together. This is a much more efficient than the bubble sort for large lists but is slower for smaller lists.

Question 13

Insertion sort:

Answer 13

orders the items as it goes. The Insertion Sort is a simple algorithm and works very well with small lists. It is not very efficient for larger lists.

Question 14

Advantages of high level compared to low level:

Answer 14

High level languages are easier to read and understand as similar to normal English so quicker to read, write and understand

Also the same high level code can be run with different processors, low level languages would be specific to one processor

Question 15

Algorithm:

Answer 15

Sequence of instructions that perform a specific task when followed

Question 16

A program is a

Answer 16

Implementation of an algorithm

Question 17

Data type:

Answer 17

What operations can be conducted on the data and how it will be stored

Question 18

Why use constants?

Answer 18

Readability - clear, ability to update, compiler optimisation - reduce memory space