Computer Science
Grade 4
20 min
Algorithm Design Challenge: Finding the Most Efficient Route
Apply learned concepts to design an efficient algorithm for finding the shortest route between two locations.
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Introduction & Learning Objectives
Learning Objectives
Define an algorithm as a set of steps to solve a problem.
Explain what makes a route 'efficient' using the concept of 'cost'.
Identify all possible routes between a start and end point on a simple map.
Calculate the total cost for each possible route by adding up the costs of its parts.
Compare the total costs of different routes to find the most efficient one.
By the end of a this lesson, students will be able to create a simple algorithm to find the best path.
Imagine you have to deliver a pizza to your friend's house. 🍕 Would you take the long, winding road or the quick shortcut? How do you decide which is best?
Today, we're going on an adventure to become route-finding experts! We will learn how to write a set of instru...
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Key Concepts & Vocabulary
TermDefinitionExample
AlgorithmA list of step-by-step instructions to finish a task or solve a problem, like a recipe for baking cookies.An algorithm to get ready for school: 1. Wake up. 2. Brush teeth. 3. Get dressed. 4. Eat breakfast. 5. Grab backpack.
Route (or Path)The specific way you travel from a starting point to an ending point.To get from your house to the park, one route might be to walk down Main Street and then turn on Oak Avenue.
NodeA single point or location on a map, like a dot representing a house, a park, or a city.On a map of your neighborhood, your house is a node, and the school is another node.
EdgeThe line that connects two nodes. It represents a part of a route.The street between your house (a node) and your friend's house (a node) is an edge.
CostA number as...
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Core Syntax & Patterns
The 'List All Paths' Rule
Start -> ... -> End
Before you can find the best path, you must first find ALL the possible paths from your starting node to your ending node. Write each one down so you don't miss any.
The 'Sum the Cost' Rule
Total Cost = Cost of Edge 1 + Cost of Edge 2 + ...
For each path you listed, add up the costs of all the small edges that make up the path. This gives you the total cost for that one route.
The 'Find the Smallest' Rule
Compare all Total Costs and choose the minimum.
After you have the total cost for every single path, compare all the numbers. The path with the smallest number is the most efficient route!
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Challenging
You need to go from Home to the Park, then the Store, then the Library. Checking every possible order of stops takes too long. What is a simple, 'good enough' rule to find a short route quickly?
A.Visit the stops in alphabetical order: Library, Park, Store.
B.From wherever you are, always go to the next closest unvisited stop.
C.Visit the stop that is farthest away first to get it over with.
D.Visit the stops in a random order each time.
Challenging
A new, super-fast shortcut road is built in your town. Your map app still suggests the old, longer route. What needs to be updated for the algorithm to find the better route?
A.The algorithm itself needs to be completely rewritten.
B.The phone's screen needs to be bigger.
C.The map data that the algorithm uses to see roads and times.
D.The color of the new road on the map.
Challenging
Algorithm A is fast but sometimes gives a route that's 1 minute longer than the best one. Algorithm B is slow but ALWAYS finds the absolute fastest route. When would it be better to use the less-perfect Algorithm A?
A.When you need an answer right now, and being 1 minute late is okay.
B.When you are planning a trip for next year and have lots of time.
C.When the computer is super powerful and can run any algorithm instantly.
D.Never, because the perfect answer is always the best one to have.
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