Understanding Algorithms

What is an Algorithm?#

An algorithm is simply a set of step-by-step instructions to solve a problem or accomplish a task. You follow algorithms every day without realising it—recipes for cooking, directions to a destination, or instructions for assembling furniture are all algorithms.

In computing, algorithms are the foundation of everything. They tell computers exactly what to do, step by step.

Why Algorithms Matter#

Understanding algorithms helps you:

• Write efficient code - Choose the right approach for the problem
• Solve complex problems - Break down big problems into manageable steps
• Think logically - Develop structured problem-solving skills
• Ace technical interviews - Algorithm questions are common in job interviews

A Simple Example: Finding the Maximum#

Let’s look at a simple algorithm to find the largest number in a list:

def find_maximum(numbers):
    if not numbers:
        return None
    
    maximum = numbers[0]
    for number in numbers:
        if number > maximum:
            maximum = number
    return maximum

# Example usage
scores = [85, 92, 78, 96, 88]
highest = find_maximum(scores)
print(f"The highest score is: {highest}")

This algorithm:

1. Starts by assuming the first number is the maximum
2. Checks each number in the list
3. Updates the maximum if a larger number is found
4. Returns the final maximum value

Common Algorithm Categories#

Sorting Algorithms#

Arrange items in a specific order. Examples include:

• Bubble Sort
• Quick Sort
• Merge Sort

Searching Algorithms#

Find specific items in a collection:

• Linear Search
• Binary Search

Graph Algorithms#

Navigate networks and relationships:

• Breadth-First Search
• Depth-First Search
• Dijkstra’s Algorithm

Big O Notation#

When discussing algorithms, you’ll often hear about “Big O notation.” This describes how an algorithm’s performance scales with input size.

Getting Started#

The best way to learn algorithms is through practice. Start with simple problems and gradually work your way up to more complex challenges. Websites like LeetCode, HackerRank, and Codewars offer excellent practice problems.

Remember: understanding the underlying logic is more important than memorising code. Once you grasp the concept, implementing it becomes much easier.