2.1

Question 1

What is abstraction?

Answer 1

Picking out important bits of information/details from the problem, ignoring the specific details that don’t matter

Question 2

What is algorithmic thinking?

Answer 2

Logical thinking and thinking methodically

Question 3

What is decomposition?

Answer 3

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

Question 4

How do you write pseudocode? What are some ways you should write it

Answer 4

Write what you have to do in words but simply just important details. 
Variable = input"..."
If...then
   Else
Print

Question 5

What does a oval mean in flow diagrams?

Answer 5

Start/stop

Question 6

What does a parallelogram mean in a flow chart?

Answer 6

Input/output

Question 7

What does a rectangle stand for in flow diagrams?

Answer 7

Processes -general instructions, processes and calculations

Question 8

What does a diamond mean in a flow diagram?

Answer 8

Decision -yes or no

Question 9

What does an arrow show in a flow diagram?

Answer 9

Show the direction you should follow

Question 10

What’s an algorithm?

Answer 10

A precise sequence of instructions.

Question 11

What’s computational thinking?

Answer 11

Computational thinking allows us to take a complex problem, understand what the problem is and develop solutions.

Question 12

What’s linear search?

Answer 12

• Look at the first item in the list
• if this is the item you’re looking for stop
• if not carry on to the next item in the list
• repeat the 2 steps before until you find the item you were looking for or you’ve checked every item

Question 13

What’s binary search?

Answer 13

• find the middle item in the ORDERED list
• if this is the item you’re looking for then stop the search
• if not then if your item is lower than the middle item you get rid of the second half of the list if it comes after the middle item you get rid of the first half of the list
• you’re left with a list half the size then repeat the 3 steps before and keep going until you find what you’re looking for

Question 14

What’s the pros and cons of linear search?

Answer 14

Pros
-fairly simple to code
-the data does need to be in a set order
Cons
-slow to process large lists-worst case scenario is searching through the whole list
-not efficient, only works well with small lists

Question 15

What’s the pros and cons of binary search?

Answer 15

Pros
-more efficient 
-more suitable for larger lists
Cons
-list has to be ordered 
-more complicated to code

Question 16

What’s a bubble sorting algorithms?

Answer 16

• look at the first two items in the list
• if they’re in the right order leave them if not swap them
• move on to the next pair the third and second and repeat the process
• repeat that process until you get to the end of the list the last item will now be correct and so it’s not included in the next pass through
• repeat going through the list until there are no swaps in a pass

Question 17

What are the pros and cons of bubble sort?

Answer 17

Pros
-simple to write the code for
-doesn't use very much memory
Cons
-inefficient, slow
-can't cope with really large lists

Question 18

What’s merge sort?

Answer 18

• split the list in half again and again until each item is individual
• merge these individual items with one other sub list each time you merge these sub lists you order them
• repeat merging the sub lists until you’ve merged all of them together

Question 19

What are the pros and cons of merge sort?

Answer 19

Pros
-more efficient and quicker than bubble and insertion for large lists
-consistent running no matter how ordered the original items are
Cons
-slower for small lists
-it uses more memory than any of the other sorting algorithms

Question 20

What’s insertion sort?

Answer 20

• look at the second item in the list
• compare all the items before it and insert the item into the right place
• repeat step 2 until you get to the last item in the list and it has been inserted into the correct place

Question 21

What are the pros and cons of insertion sort?

Answer 21

Pros
-easy to code, intuitive way of thinking about it
-copes very well with small lists, doesn’t require much additional memory
Cons
-doesn’t cope very well with large lists
-best case scenario requires n-1 comparisons
-worst case scenario requires n(n-1)/2 comparisons

Question 22

What’re two advantages of problem decomposition?

Answer 22

• spend less time overall because of having a plan breaking down the bigger problem
• create functions that could be reused in a different problem
• different people can work on different aspects at the same time