Algorithms

Question 1

Name 3 characteristics of an Algorithm

Answer 1

1. Unambiguous
2. Sequence of steps
3. Provides a solution to a problem

Question 2

What does an OVAL indicate in flowcharts?

Answer 2

start/end of an algorithm

Question 3

What does a ROUNDED RECTANGLE indicate in flowcharts?

Answer 3

indicates a process to be carried out

Question 4

What does a DIAMOND indicate in flowcharts?

Answer 4

indicates a decision to be made

Question 5

What does a PARALLELOGRAM indicate in flowcharts?

Answer 5

input/output

Question 6

What does an ARROW indicate in flowcharts?

Answer 6

displays the logical flow of the algorithm

Question 7

What is a variable?

Answer 7

A variable holds a value that can be changed or used throughout the program

Question 8

Give 3 examples of a date type

Answer 8

1) Integer
2) String
3) Boolean

Question 9

What is a boolean?

Answer 9

a binary variable that can have one of two possible values, 0 (false) or 1 (true).

Question 10

What is a constant?

Answer 10

A constant is always constant- it stays the same.

Question 11

What is bubble sort?

Answer 11

The bubble sort algorithm starts at one end of the list and compares pairs of data items. If they are in the wrong order, they are swapped. The comparison of pairs continues to the end of the list.

Question 12

What are the 4 steps of bubble sorting (ascending order)?

Answer 12

1. Start at the beginning of the list
2. compare the values in position 1 and position 2. If they are not in ascending order, swap them
3. compare values in position 2 and 3 and swap if necessary
4. Continue to the end of the list

Question 13

What is Merge Sort?

Answer 13

Merge sort is a sorting algorithm that divides a list into two smaller lists and then divides these until the size of the list is one.

Question 14

define recursion

Answer 14

a process that is repeated

Question 15

define brute force

Answer 15

an algorithm design that does not include any techniques to improve performance, but instead relies on computing power to try all possibilities until the solution to a problem is found

Question 16

give an example of a brute force algorithm

Answer 16

bubble sort

Question 17

define ‘divide and conquer’

Answer 17

an algorithm design that works by dividing a problem into small sub problems, until they are easy to solve.The solutions to these are then combined to give a solution to the complete problem.

Question 18

What are the 5 steps of binary search?

Answer 18

1. Select the median item of the list
2. Stop if the median item is equal to the search item
3. If the median is too high then repeat 1 and 2 with the sublist to the left
4. If the median is two low then repeat 1 and 2 with the sublist to the right
5. Repeat steps 3 and 4 until the item has been found

Question 19

What is computational thinking?

Answer 19

the thought processes involved in formulating problems and their solutions so that the solutions are represented in a form that can be effectively carried out by a computer.

Question 20

What are the 3 skills of computational thinking?

Answer 20

• algorithm design
• decomposition
• abstraction

Question 21

what is decomposition?

Answer 21

breaking a problem down into smaller, more manageable parts, which are easier to solve

Question 22

what is abstraction?

Answer 22

the process of removing or hiding unnecessary detail so that only the important points remain.

Question 23

Define subprograms

Answer 23

a self contained module of code that preforms a specific task. It can be ‘called’ by the main program when it is needed.