fundamentals of algorithms

aqa gcse computing

what is an algorithm

a sequence of steps that can be followed to complete a task.

what is decomposition

Decomposition means breaking a problem into a number of sub-problems so that each sub-problem accomplishes a task

what is abstraction

Abstraction is the process of removing unnecessary detail from a problem.

what is integer used for

whole number

what is a real used for

adds opperation that work on real numbers

what is a boolean used for

true or false

what is a character used for

individual letters/symbols

what is a string used for

sequence of letters

what is a float used for

decimals

what is the base of a decimal ?

base 10

what is the base of a binary ?

base 2

what is the base of a hexidecimal ?

base 16

why is hexadecimal used instead of binary

larger numbers can be represented are fewer digits

what is a sorting algorithm ?

Sorting algorithms are precise step-by-step instructions that a computer can follow to efficient sort data in massive data sets

2 most common sorting algorthim

• bubble sort

• merge sort

what is a merge sort ?

A merge sort is a sorting algorithm divides a dataset into smaller sub-datasets and merging them back together in the correct order

how do you peform a merge sort ? ( 3)

1. divide data set into individual datasets

2. merge pairs of subdatas together by comparing the first value in each dataset

3. repeat step 2 into all merged into one data set

what is a bubble sort ?

A bubble sort is a simple sorting algorithm that starts at the beginning of a dataset and checks values in 'pairs' and swaps them if they are not in the correct order

2 advantages of a merge sort

• Suitable for large datasets

• Performs well no matter how unorganised the data is

1 advantages of a bubble sort

• Simple to understand and implement

2 disadvantages of a merge sort

• Uses a lot of memory

• More complex to implement

2 disadvantages of a bubble sort

• Slow for large datasets

• Inefficient, as ititerates through the data multiple times

what is a searching algorithm ?

• Searching algorithms are precise step-by-step instructions that a computer can follow to efficient locate specific data in massive datasets

2 common searching algorithm

• Binary search

• Linear search

what is a linear search ?

A linear search starts with the first value in a dataset and checks every value one at a time until a values have been checked

how do you peform a linear search ?

1. check first value

2. if its the value your looking for

3. move to the next value and check

4. repeat

what is a searching algorithm ?

precise step-by-step instructions that a computer can follow to efficient

locate specific data in massive datasets

2 common searching algorithm

• binary search

• linear search

what is a binary search ?

keeps halving a dataset by comparing the target value with the middle value, going

left if smaller,right if bigger, until it finds the value or realises it's not there

should the data be in order for a binary search or linear ?

binary

how do you peform a binary search ?

1. identify middle value

2. compare value if its bigger then the one your loooking for

3. create a new list with the value on the left of the middle value

4. if its smaller create a new list with the values on the right of the middle value

what is algorithm efficency

is how much time it takes to complete an algorithm

3 examples of compytational thinking

• Algorithmic thinking

• Decomposition

• Abstraction

define decomposition

Decomposition is the process of breaking down a large problem into a set of smaller problems

3 positives of decomposition

• Smaller problems are easier to solve

• Each smaller problem can be solved independently of the others

• Smaller problems can be tested independently

define abstraction

process ofremoving unnecessary details from a problem to focus on the important

features for implementing a solution