Module 3: Technical Preparation
Building Arrays and Moving Windows

Module 3 focuses on working with 2D arrays and applying the moving window technique to solve array-based problems. These concepts are fundamental in technical interviews and coding assessments, especially for data processing and algorithm implementation.

Through this module, you'll build a solid understanding of how to create, access, and manipulate multi-dimensional arrays, as well as how to efficiently process arrays using sliding window approaches.

Introduction to 2D Arrays

This video reviews the concept of 2D arrays in Python (also known as matrices or nested lists):

• Understanding the structure of 2D arrays
• How to represent grids, tables, and matrices in code
• Basic operations with 2D arrays

Building 2D Arrays (Part 1)

Learn how to create and initialize 2D arrays:

• Different methods for creating 2D arrays in Python
• Initializing arrays with specific values
• Common pitfalls and how to avoid them

Building 2D Arrays (Part 2)

This video explores planning and executing operations with 2D arrays:

• Planning algorithms that use 2D arrays
• Traversing 2D arrays with nested loops
• Accessing and modifying elements in a 2D array

Building 2D Arrays (Part 3)

Continue exploring operations with 2D arrays:

• Working with rows and columns
• Implementing common patterns for processing 2D arrays
• Handling edge cases in 2D array operations

Building 2D Arrays (Part 4)

Reflecting on 2D array implementations:

• Analyzing the time and space complexity of 2D array operations
• Optimizing 2D array algorithms
• Real-world applications of 2D arrays

Understanding Moving Windows (Part 1)

Introduction to the moving window (sliding window) technique:

• What is a moving window and when to use it
• Identifying problems suitable for moving window solutions
• Understanding the basic approach

Planning Moving Windows (Part 2)

Planning your approach to moving window problems:

• Determining window size and movement pattern
• Planning how to process data within the window
• Considering edge cases and boundary conditions

Implementing Moving Windows (Part 3)

Beginning the implementation of moving window solutions:

• Setting up the initial window
• Processing data within the window
• Moving the window effectively

Implementing Moving Windows (Part 4)

Continuing the implementation with more complex scenarios:

• Advanced moving window patterns
• Optimizing the window movement
• Handling special cases

Reflecting on Moving Windows (Part 5)

Analyzing and reflecting on moving window implementations:

• Time and space complexity analysis
• Comparing different moving window approaches
• Applications of moving windows in real-world problems

In this guided project, you'll apply your understanding of 2D arrays and moving window techniques to solve array-based problems. You'll work through exercises involving array manipulation and analysis of time complexity (Big-O). First watch the videos, then complete the rest of the guided project on your own.

Project Resources

GCA Preparation - General Practice

As part of this module, you'll continue practicing for the General Code Assessment (GCA).

1. Go to the LeetCode Problems section
2. Attempt at least 10 problems on your own, applying the 4-step problem-solving framework
3. Focus on problems involving 2D arrays and sliding window techniques
4. Pay special attention to time and space complexity analysis

Recommended LeetCode Problems

The following medium-difficulty problems will help you practice applying the problem-solving framework to array manipulation and sliding window scenarios:

• Spiral Matrix - Practice traversing a 2D array in a spiral pattern
• Rotate Image - Manipulate a 2D matrix by rotating it 90 degrees
• Maximum Subarray - Apply sliding window concepts to find maximum sum
• Max Consecutive Ones III - Use sliding window to handle sequence manipulation
• Game of Life - Process a 2D grid with specific rules

To reinforce your understanding of 2D arrays and moving window techniques, complete the following activities:

1. Choose at least 3 problems from the recommended list above
2. For each problem:
   • Apply the four-step problem-solving framework (Understand, Plan, Execute, Reflect)
   • Document your thought process for each step
   • Implement your solution and test it with the provided test cases
   • After solving, review the Discussion section to see different approaches
   • Analyze the time and space complexity of your solution
3. Reflect on how 2D array access patterns affect the efficiency of your algorithms
4. Practice explaining your approach as if you were in a technical interview

Taking the GCA:

1. Take the official GCA at this link: BloomTech GCA Test

2D Arrays and Matrices

Sliding Window Technique

Time Complexity