Computer Science
Grade 6
20 min
Designing Efficient Algorithms: Tips and Tricks
Explore strategies for designing more efficient algorithms, such as breaking down problems into smaller parts.
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1
Introduction & Learning Objectives
Learning Objectives
Define 'algorithm' and 'efficiency' in their own words.
Explain the difference between an efficient and an inefficient algorithm using a real-world example.
Count the number of steps an algorithm takes to solve a simple problem.
Describe the process of a Linear Search.
Describe the process of a Binary Search.
Determine which search algorithm is more efficient for a sorted list of items.
Imagine you have to find a friend's name in a giant phone book. Would you start at page 1 and read every name, or would you jump to the middle and see which half their name is in? 🧐
In this lesson, we'll learn about algorithms, which are like recipes for computers. We'll discover how to measure an algorithm's 'efficiency'...
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Key Concepts & Vocabulary
TermDefinitionExample
AlgorithmA step-by-step list of instructions to solve a problem or complete a task.A recipe for baking a cake is an algorithm. It has a list of ingredients (inputs) and a set of instructions to follow in order to get a cake (output).
EfficiencyA measure of how fast an algorithm can solve a problem using the fewest steps or resources (like time or computer memory).An efficient way to clean your room is to put each item away in its proper place. An inefficient way is to throw everything into one big pile first, then sort the pile.
Step / OperationA single action or instruction within an algorithm.In an algorithm for finding a number in a list, one 'step' is looking at a single number and asking, 'Is this the one I'm looking for?'
Linear SearchA...
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Core Syntax & Patterns
The 'One-by-One' Method (Linear Search)
Start at the beginning of a list. Check the first item. If it's not what you want, move to the next item. Repeat until you find it or reach the end.
Use this when you don't know anything about the list, especially if it's not sorted. It's simple but can be very slow for long lists.
The 'Divide and Conquer' Method (Binary Search)
1. Go to the middle of a SORTED list. 2. If the middle item is what you want, you're done! 3. If your item is smaller, repeat the search on the first half. 4. If your item is larger, repeat the search on the second half.
Use this ONLY on sorted lists. It's much, much faster than Linear Search for long lists because it eliminates half the items with every step.
4 more steps in this tutorial
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Challenging
You are designing a game to find a hidden treasure on a 10x10 grid. To guarantee finding it efficiently, what is the best search algorithm for your character?
A.Start at the top-left and check every square in order, row by row.
B.Check 20 random squares and hope for the best.
C.Only check the four corner squares.
D.Keep returning to the center square to 'reset' the search.
Challenging
A program checks if a maze is solvable. Algorithm 1 finds ALL possible paths from start to finish. Algorithm 2 stops as soon as it finds just ONE path. Why is Algorithm 2 more efficient?
A.It uses less memory to store the paths.
B.It proves the maze is harder to solve.
C.Finding all paths is impossible for a computer.
D.It avoids unnecessary work by stopping as soon as the problem is solved.
Challenging
You have two movie recommendation algorithms. Algorithm FAST is quick but sometimes wrong. Algorithm SMART is slow but always gives great recommendations. For a brand new user, which is the better choice to make a good first impression?
A.Algorithm FAST, because users don't like to wait.
B.Neither, you should ask the user what they want to watch.
C.Algorithm SMART, because a great recommendation is more important than speed for a first impression.
D.Use both and show the user two different recommendations.
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