Algorithms

Question 1

What are the three types of computational thinking?

Answer 1

abstraction - focusing on just the important details of the problem
decomposition - breaking a problem down into smaller parts
algorithmic thinking - creating a step by step solution to the problem

Question 2

Linear search

Answer 2

checks each item in the list one by one until it finds what it is looking for
adv - doesn’t need to be ordered
disadv - not efficient, takes time

Question 3

Binary search

Answer 3

find middle item. if it is the item you are looking for then stop. otherwise compare to the item you are looking for and then half the half you have left over. Then repeat until you are finished.
adv - More efficient
disadv - list has to be ordered

Question 4

Bubble sort

Answer 4

Checks the first two items in a list, swaps them if they are in the wrong order and then moves onto the next two items and repeats the process. Once it has passed through the list once it goes through again until none of the items need swapping.
+ Simple.
– Takes a long time

Question 5

Merge sort

Answer 5

Finds the middle item (n+1)/2 and splits the list in half. Repeats this step until the list is split into individual items (sub-lists). It them merges (joins) the sublists in pairs. Each time the sublists are paired they are sorted into the correct order.
+ Efficient
– Slow

Question 6

Insertion sort

Answer 6

Looks at the second item in a list and compares it to the items that are in front of it, then inserts it into the right place. It then moves to the next item in the list and repeats these steps.
+ Quick for sorting small lists
– slow withlong lists

Question 7

Flowchart symbols

Answer 7

Oval - start/stop
Diamond - decision
Rectangle - action

Question 8

input, process, output

Answer 8

input - what info is entered
process - the thing that happens to the input
output - the result of the process

Question 9

structure diagram

Answer 9

shows how a problem is broken down

Question 10

common errors

Answer 10

syntax - mistakes using language e.g.comma or quotation mark
logic - mistake in the programs source code.
runtime - error whilst executing the program

Question 11

trace tables and their uses

Answer 11

used to determine outputs from a program as it runs. They enable a programmer to find errors in their programs.