Programming logic

1. GCSE Computing
L4 – Logic

2. The knights tour. A knight in chess can move either two
squares horizontal and one square vertical or two squares
vertical and one square horizontal. Example below.
Starter

3. The challenge:
Visit each space on the grid
exactly once
End up back at square one
Starter

4. Know what abstraction is
Understand that programs can be broken down into
smaller pieces
Be able to understand the terms modelling,
decomposition, generalisation and graphs
Objectives

5. Decomposition
Break a big task into several smaller
tasks
Instead of ‘visit all squares at least
once’,
break it down into a series of specific
steps
“Divide and conquer”

6. See if you can solve the problem
Main 1 – Puzzling Tours

7. Which is easier? Why?

8. Graphs
A diagram of a system
Made up of nodes and edges
Can be an extremely useful way of
modelling a problem

9. Lateral Thinking

10. Lateral Thinking

11. Lateral Thinking

12. Lateral Thinking

13. Lateral Thinking

14. Lateral Thinking

15. Lateral Thinking

16. Complete the graph of the knights tour to show all moves.
Main 2 – Knight’s Tour Graph

17. Modelling
• Create a representation of a system
• Hide unnecessary data
• Reduce complexity

18. Modelling
• Create a representation of a system
• Hide unnecessary data
(e.g. physical steps between moves)
• Reduce complexity
(e.g. having to jump over squares)

19. Generalisation
• There are many interpretations of
this word
• Replacing many things, with one thing
e.g. functions, mail merge
• Adapting the solution for one problem,
to solve another
• e.g. We turned Knight’s Tour into a
graph - we can use the same idea
elsewhere

20. London

21. London

22. London

23. A Graph

24. An Abstraction

25. Walking Times

26. Walking Times

27. We are going to use the map of the London Underground to
find the fastest route from one location to another. Remember
the Underground map is a graph and an abstraction.
Main 3 – Zombie Apocalypse

28. Abstraction
• Modelling
e.g. creating a graph
• Decomposition
e.g. listing the steps to find the
solution
• Generalisation
e.g. applying the same technique to
a similar problem

29. Abstraction
• Modelling
Ignore the physical distance between
stations
• Decomposition
Find the steps you need to reach
your goal
• Generalisation
Use this for a different journey in
London

30. Using this PowerPoint complete the key terms worksheet.
Main 4 – Key Terms

31. See if you can complete the bridges of Konigsberg. You must
visit every island by only crossing each bridge once.
Plenary