2.1 Algorithms

Question 1

Define abstraction

Answer 1

Removing unnecessary details

Question 2

Define decomposition

Answer 2

Breaking complex problems into smaller parts
Easier to work with
Solve at the same time
Shown in structure diagram

Question 3

Define algorithmic thinking

Answer 3

Identifying individual steps needs to reach the solution
Allows to automate solutions

Question 4

What are the two searching algorithms

Answer 4

Binary
Linear

Question 5

Describe how to do a binary search

Answer 5

Look at middle number
Compare to target number and discard half of list to big/ to small to the target
Process starts again until target is found

Question 6

Pros of binary search

Answer 6

Efficient and quicker than linear
Fewer comparisons

Question 7

Cons of binary search

Answer 7

List must be in order

Question 8

What is linear search

Answer 8

Each item in the list is checked one at a time from left to right until target number is found

Question 9

Pros of linear search

Answer 9

Doesn’t need to be in order
Simple to run and create

Question 10

Cons of linear search

Answer 10

Very slow
Inefficient and requires lots of comparisons

Question 11

What flowchart diagram is this

Answer 11

Start/end

Question 12

What flowchart diagram is this

Answer 12

Decision

Question 13

What flowchart diagram is this

Answer 13

Input or output

Question 14

What flowchart symbol is this

Answer 14

Process

Question 15

What flowchart symbol is this

Answer 15

Sub program

Question 16

What is a syntax error

Answer 16

Error in spelling or grammar used when coding which causes an error message

Question 17

What is a logic error

Answer 17

Mistake in the programs code which results in unexpected behaviour although the code is correct

Question 18

What is a trace table

Answer 18

Table that follows the values of variables to check for accuracy

Question 19

What is iteration

Answer 19

A FOR loop - loop number is known as
A WHILE loop - loop number is unknown

Question 20

What is selection

Answer 20

IF
ELSE
ELIF

Question 21

What are the three sorting algorithms

Answer 21

Bubble
Insertion
Merge

Question 22

What is bubble sort

Answer 22

Compares two numbers
Numbers are swapped if left is greater
Process repeated until list is in order
Goes through list an extra time to check its in order

Question 23

Pros and cons of bubble sort

Answer 23

Pros - simple to create/run
Cons - slow,inefficient and requires lots of comparisons

Question 24

What is insertion sort

Answer 24

Puts first number in sorted list
Compares rest of numbers in un sorted list with sorted list
Inserts it into the correct place

Question 25

Pros and cons of insertions sort

Answer 25

Pros- faster and fewer comparisons Cons-more complicated than bubble

Question 26

What is merge sort

Answer 26

Splits into individual lists Single numbers into groups of two sorting as they merge Groups of 2 into groups of 4 Repeat until it’s one list

Question 27

Pros and cons of merge sort

Answer 27

Pros - Efficient for long lists Cons - inefficient for small lists or lists that are slightly out of order