Module 2 Lesson 7: Introduction to Algorithms

If Data Structures are the containers, then Algorithms are the sets of instructions on how to use those containers. Every time you search for a friend on social media or sort your emails by "Date," you are running an algorithm.

Lesson Overview

In this lesson, we will cover:

The Definition: What exactly is an algorithm?
The Recipe Analogy: How algorithms mirror real life.
Input-Process-Output: How algorithms interact with data.
Efficiency: Why some instructions are better than others.

1. What is an Algorithm?

An algorithm is simply a step-by-step procedure for solving a problem or performing a task.

It is not a piece of code. It is the Logic behind the code.

Problem: Sorting a pile of cards.
Algorithm: "Look at every card, find the smallest one, put it first. Repeat."
Code: The specific Python lines you write to do that.

2. Algorithms in Everyday Life

You use algorithms all the time without knowing it:

Cooking: A recipe is an algorithm. If you follow the steps correctly, you get a cake.
GPS: Calculating the fastest route from point A to point B is a complex algorithm.
Recommendations: Netflix suggesting a movie based on what you’ve seen is an AI algorithm.

3. The Three Qualities of a Good Algorithm

Not all instructions are created equal. A "good" algorithm must be:

Finite: It must eventually stop (no infinite loops!).
Unambiguous: Every step must be clear and simple.
Effective: It must actually solve the problem it was designed for.

4. How Algorithms Work with Data

Algorithms and Data Structures are like Peanut Butter and Jelly—they belong together.

The Data Structure holds the information.
The Algorithm processes it.

Example: If your data is a List of numbers, you need a Sorting Algorithm to put them in order.

Practice Exercise: The Human Algorithm

Imagine you are talking to someone who has never made a bowl of cereal. Write a step-by-step "algorithm" for them. Be as specific as possible.

Step 1: ...
Step 2: ...
Step 3: ...

Notice how hard it is to be perfectly clear! That is the challenge of programming.

Quick Knowledge Check

How is an algorithm different from code?
Name one real-world example of an algorithm.
What are the three core qualities of a good algorithm?
Can an algorithm exist without a computer?

Key Takeaways

Algorithms are logical instructions, not just code.
The better your algorithm, the faster your program.
Every algorithm takes an Input, performs a Process, and yields an Output.

What’s Next?

Now that we know what they are, let's learn how to find things! In Lesson 8, we’ll explore Searching Techniques—how to find one specific needle in a digital haystack.