Unit 6 - Algorithms✔️

Question 1

what are algorithms?

Answer 1

a set of instructions for solving a problem or completing a task

Question 2

what does abstraction mean in relation to algorithms?

Answer 2

abstraction - involves removing unnecessary detail from a problem so that you can focus on the essential components

Question 3

what is decomposition in relation to algorithms?

Answer 3

decomposition involves breaking down a large problem into small sub-problems - then the sub problems can be broken down further until each small task is manageable

Question 4

advantages of decompostion?

Answer 4

-problem becomes easier to solve when it consists of a number of small subtracts or modules

-some modules can be reusable in other programs saving development time

Question 5

why is a structure diagram used?

Answer 5

used to show how a problem is broken down into sub sections

Question 6

define algorithm thinking?

Answer 6

an approach to solving problems by the use of algorithms

Question 7

why might a linear search be used?

Answer 7

if the list to be searched is not sorted it is not possible to do a binary search

Question 8

define how a linear search works?

Answer 8

each item in the list is checked against the search item in order

Question 9

define how a binary search works?

Answer 9

the middle item is checked first if the item searched for is greater then it - the items to the left will be discarded and a binary search will be carried out on the right side by repeating the process of splitting the middle item and discarding the side which does not contain the desired item

Question 10

why might a binary search not always work?

Answer 10

only works on a sorted list

Question 11

4 examples of data that needs to be sorted?

Answer 11

-directories
-house numbers
-library books
-stock in a warehouse

Question 12

why are computers more efficient with a sorted list?

Answer 12

they can use a binary search which is far more efficient then a linear search

Question 13

name three algorithms which can be used to sort lists of data?

Answer 13

-bubble sort
-insertion sort
-merge sort

Question 14

which algorithm is generally the most efficient?

Answer 14

merge sort is generally faster to sort lists

Question 15

features of an insertion sort?

Answer 15

-algorithm sorts one data item at a time

Question 16

what are the steps of merge sort?

Answer 16

1)divide the unsorted list in two
2)continue to divide lists in two until just one item in each list
3)merge each list back until there is only one list remaining (which will be fully sorted)

Question 17

what are the steps for bubble sort?

Answer 17

1)compare the item with the one next to it
2)if the one next to it is less - swap the items
3)repeat for all the other items
4)at the end of one pass through the list the largest item is at the end of the list

Question 18

how does insertion sort work?

Answer 18

1)one item is taken from the list and placed in the correct position
2)this is repeated until there are no more unsorted items in the list