Lecture Notes: Mastering Data Structures and Algorithms for Coding Interviews

Introduction

• Many programmers struggle with coding interviews despite extensive study of data structures and algorithms (DSA).
• Focus on effective learning strategies to crack coding interviews.

Choosing the Right Programming Language

• Most learners start DSA with a programming language they already know.
• Importance of language during time-sensitive coding interviews:
  • Mastery in a language is essential.
  • Recommendation: Python
    • No boilerplate code, resembles pseudo-code.
    • Widely used in industry; interviewers are comfortable with it.
    • Enables effective communication of ideas.

Learning Strategy: Just In Time Learning (JET)

• Focus on acquiring knowledge and skills exactly when needed.
• Avoid overwhelming yourself with obscure topics.
• Start with core concepts relevant to coding interviews.

Essential Concepts in DSA

Big O Notation

• Introduced by Donald Knuth in 1968; crucial for algorithm analysis.
• Helps in comparing algorithm efficiency based on:
  • Time complexity
  • Space complexity
• Understand common time complexities:
  • O(1), O(log n), O(n), O(n log n), O(n²), O(2ⁿ), O(n!)

Data Structures

• Fundamental building blocks that impact algorithm performance.
• Key data structures to learn:
  • Arrays
  • Linked Lists
  • Stacks
  • Queues
  • Binary Trees
  • Hash Tables
• After mastering basic structures, consider learning:
  • Heaps
  • Graphs
  • Tries
  • Disjoint Sets
• Understand internals and time complexities of operations on data structures.

Algorithms

Categories of Algorithms

1. Specific to Data Structures:
   • Searching and sorting algorithms, two pointers, sliding window techniques.
2. General Techniques:
   • Recursion, dynamic programming, backtracking, greedy algorithms.

• Utilize DSA Master for core algorithms necessary before proceeding.

Implementation Strategy

• Implement algorithms from scratch to deepen understanding and avoid dependency on libraries.
• Analyze the time complexity of implemented algorithms for a better grasp of their efficiency.

Practice Problems

• Focus on practicing the most commonly asked coding problems.
• Recommended collections:
  • Blind 75
  • Top Interview 150
• Created Interview Master 100:
  • Top 100 interview problems arranged progressively.
  • Helps beginners build knowledge without feeling overwhelmed.
• Continue solving problems on LeetCode post-completion of Interview Master 100.

Final Thoughts

• Learning DSA is a means to an end—success in coding interviews requires consistent practice.
• Keep solving problems to improve and prepare for actual interview scenarios.

Instructor Information

• Name: Sahil
• Encouragement for further learning and practice.