What's covered
Key facts
Abstraction: Ignoring Irrelevant Detail
Abstraction in computing means ignoring detail that is not needed to solve the problem.
Algorithm Design: Step-by-Step Logic
Clear, ordered steps make an algorithm easier for others to follow and check.
Decomposition: Breaking Down Problems
Decomposition is breaking a problem into smaller parts.
Pattern Recognition
Spotting that two problems both need a loop is pattern recognition between those problems.
What is an Algorithm?
An algorithm is a set of step-by-step instructions for solving a problem.
Abstraction: Ignoring Irrelevant Detail
Abstraction helps you focus only on what is relevant to the problem.
Algorithm Design: Step-by-Step Logic
Designing an algorithm before coding helps avoid mistakes that would be costly to fix later.
Decomposition: Breaking Down Problems
Big, complex programs benefit most from decomposition: that's exactly when one person can't hold the whole solution in their head.
Pattern Recognition
Pattern recognition means spotting similar features between problems.
What is an Algorithm?
A blank piece of paper is not an algorithm: there are no instructions.
Practice questions with answers
A taste of the 40 questions in this topic, answers marked. Sign up to practise the full set with spaced repetition.
What does abstraction help us do?
- •Add all possible detail to a problem
- ✓Focus only on what's relevant
- •Make the code run more slowly
- •Use more memory than needed
What does algorithm design mean?
- •Drawing the user interface and choosing the colours of the buttons
- ✓Planning the step-by-step logic that solves a problem before writing any code
- •Testing a finished program with example inputs to find bugs
- •Writing the final program code in Python or another language
Why use decomposition?
- •Smaller parts always run faster on CPUs
- ✓Smaller parts are easier to solve
- •Smaller parts make programs work alone
- •Smaller parts use no memory at all
Why spot patterns in programming?
- •Make all programs identical to each other
- •Reduce the number of variables to zero
- •Remove the need for any kind of testing
- ✓Solve similar problems the same way
Is a recipe an algorithm?
- •No, a recipe has no definite end point
- •No, algorithms must be written in code
- •Yes, because it uses variables and loops
- ✓Yes, it lists ordered steps
An Underground map showing straight lines is abstraction because:
- ✓It ignores the real curved track shape
- •It includes all the train schedules
- •It shows every house along each line
- •It shows the GPS of each station exactly
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