Crack the coding interviews with LeetCode Blind 75 patterns

Overview#

Coding interviews are a critical part of the hiring process for software engineering roles in the tech industry. They typically involve solving algorithmic and data structure problems, and sometimes domain-specific tasks. These interviews aim to assess a candidate’s problem-solving abilities, coding skills, and understanding of computer science fundamentals.

Why preparing for the coding interviews is important

The competitive nature of the tech industry means that many qualified candidates compete for the same positions. Thorough preparation can make a significant difference, because it helps candidates to quickly and accurately solve problems under pressure. By practicing extensively, candidates become familiar with common problem types and can develop efficient problem-solving strategies.

Practice a pool of problems

One effective method for interview preparation is to practice from a curated pool of problems. These problems are selected to cover various topics and patterns that frequently appear in coding interviews. By focusing on a well-rounded set of questions, candidates can ensure they are prepared for the diverse challenges they may face during the interview.

LeetCode is one of the most widely used platforms for coding practice and interview preparation. It offers a vast collection of problems categorized by difficulty and topic, along with detailed solutions and discussions. However, the extensive set of problems can make it challenging for candidates to prepare effectively for technical interviews. This is why, instead of practicing thousands of problems, we’ll focus on a curated pool of selected problems known as the Blind 75.

Introduction to Blind 75#

Blind 75 is a curated list of 75 coding interview questions that are considered essential for preparing for technical interviews, particularly for software engineering roles. This list was created by a software engineer Yangshun Tay from Blind, a community where tech professionals discuss various topics, including job interviews and career advice. The Blind 75 list has gained popularity due to its focus on fundamental problems that frequently appear in coding interviews.

The problems included in the Blind 75 list are carefully selected to cover a broad range of topics that are commonly asked in technical interviews. These topics include arrays, linked lists, dynamic programming, trees, graphs, intervals, strings, binary search, heap, and backtracking. Each problem is chosen to help candidates understand and master key concepts, techniques, and patterns necessary for solving a wide variety of coding challenges.

How is the Blind 75 structured on the internet?#

The Blind 75 problems are typically organized by data structures and difficulty levels. Here is the complete list of problems categorized based on data structure:

Array#

The following are the array-related problems in Blind 75. There are three easy problems and seven medium-difficulty problems.

Binary#

The following are the binary-related problems in Blind 75. There are four easy problems and one medium-difficulty problem.

Dynamic programming#

The following are the dynamic programming-related problems in Blind 75. There is one easy problem and ten medium-difficulty problems.

Graph#

The following are the graph-related problems in Blind 75. There are seven medium problems and one hard-difficulty problem.

Interval#

The following are the interval-related problems in Blind 75. There is one easy problem and four medium-difficulty problems.

Linked list#

The following are the linked list related problems in Blind 75. There are three easy problems and two medium-difficulty problems.

Matrix#

The following are the matrix-related problems in Blind 75. There are four medium-difficulty problems.

String#

The following are the string-related problems in Blind 75. There are three easy problems, six medium-difficulty problems, and one hard-to-solve problem.

Tree#

The following are the tree-related problems in Blind 75. There are four easy problems, seven medium-difficulty, and three hard-to-solve problems.

Heap#

The following are the heap-related problems in Blind 75. There is one easy problem and two hard-to-solve problems.

How is the Blind 75 structured on Educative?#

On Educative, the Blind 75 problems are structured in a course format that guides learners through each problem step-by-step. Instead of organizing problems by data structures, they are categorized by coding patterns. This approach helps learners recognize and understand recurring patterns in coding problems, making it easier to apply similar strategies to unseen problems.

With the same set of 75 problems, we have covered 23 patterns. These patterns are as follows:

The course is offered in five programming languages: Python, C++, Java, JavaScript, and Go, allowing learners to choose the language most relevant to their needs. Explore the course variants available in different programming languages below:

Why use pattern-based categorization instead of data structure-based categorization?#

In the context of coding problems, patterns are recurring solutions or strategies that can be applied to solve similar types of problems. Instead of focusing solely on data structures, which are more about the organization and storage of data, pattern-based categorization emphasizes the methodology and approach to solving problems. 

Recognizing and understanding patterns is important for several reasons:

• Efficiency in problem-solving: Patterns provide a blueprint for approaching a problem. Once you recognize a problem as fitting a particular pattern, you can apply the known solution strategy, which saves time and effort in devising a new approach from scratch.

• Transferable knowledge: Learning patterns helps in transferring knowledge across different problems. Even if the problems differ in specifics, the underlying pattern remains the same, allowing you to apply the same strategy to multiple scenarios.

• Enhanced understanding: Understanding patterns deepens your grasp of problem-solving techniques. It moves beyond rote memorization of solutions and toward a more conceptual understanding of why certain approaches work, which is essential for adapting to new and unfamiliar problems.

• Preparation for interviews: In coding interviews, problems are often designed around common patterns. Recognizing these patterns can give you an edge, as you can quickly identify the nature of the problem and apply a proven solution strategy.

Pattern-based categorization helps learners develop a toolkit of broadly applicable strategies, making them more universal and effective problem solvers. This approach not only assists in mastering specific problems but also builds a strong foundation for tackling new challenges in the future.

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Why choose Blind 75 on Educative#

Educative offers several features that make it a valuable platform for learning Blind 75:

• Pattern-based focussed learning: As compared to other platforms that just bombard learners with an extensive pool of problems, Educative provides pattern-based focussed learning that teaches the underlying patterns in solving coding problems.

• Difficulty distribution: Educative starts with easier coding interview patterns, gradually increasing the difficulty level to medium, and finally ending with the hardest patterns to provide an effective interview preparation.

• Premium content: Educative includes a few premium LeetCode problems to ensure comprehensive interview preparation.

Where to go next?#

If you have enough time to learn more or you want to be a pro in the interview, then you can explore the following:

• Educative-99

• Grokking the coding interview patterns

• Dynamic programming

Educative-99#

Educative-99 is a special list of curated coding problems to help learners ace their coding interview preparation in a reasonable amount of time. It is designed for focused and systematic blitz pattern-based interview preparation. You can explore the course variants available in different programming languages below:

Grokking coding interview patterns#

To effectively prepare for coding interviews, many candidates opt for specialized courses that teach coding interview patterns. Platforms like Algo Monster and LeetCode offer various resources to help learners master these patterns. However, at Educative, we provide a unique and comprehensive approach. Our Grokking Coding Interview Patterns course stands out with its in-depth coverage and practical focus. The course includes individual lessons that introduce each pattern, discussing techniques, algorithms, and data structures tailored to address common coding challenges. Our course ensures thorough preparation by covering a total of 26 patterns. You can explore the course variants available in different programming languages below:

Dynamic programming#

Dynamic programming is one of the most frequently asked question patterns. Almost all companies ask questions relevant to dynamic programming. To master dynamic programming, you can explore the course variants available in different programming languages below:

Conclusion#

In conclusion, preparing for coding interviews is essential for aspiring software engineers aiming to secure roles in the competitive tech industry. The LeetCode Blind 75 offers a focused approach, emphasizing the importance of mastering fundamental problems that are frequently encountered in technical interviews. Educative enhances this preparation by structuring these problems around coding patterns, which not only helps in solving specific problems but also equips learners with versatile problem-solving strategies.

The Blind 75 list, with its comprehensive coverage of key topics and patterns, provides a solid foundation for tackling a wide variety of coding challenges. Educative’s interactive, pattern-based learning approach, supported by AI-enabled feedback and extensive test cases, ensures that learners gain a deep understanding of these patterns and learn how to apply them effectively.