The hottest Algorithms Substack posts right now

And their main takeaways
Category
Top Technology Topics

Idea behind Bit shifting [Math Monday]

Technology Made Simple • 39 implied HN points • 19 Apr 22
🕹 Technology Math Algorithms Computer Science
  1. Understanding Binary Math is crucial for coding interviews. Practice is key for mastering bit shifting.
  2. Familiarity with Modular Arithmetic, Number Systems, and Recursion is important. They are foundational math skills for solving interview questions.
  3. Being able to identify when to use Mod function, transitioning between number bases, and coding recursion are critical for successful problem-solving.

✋ Newsletter #38: Me Too

Women On Rails Newsletter - International Version • 19 implied HN points • 03 Nov 22
🕹 Technology Web Development Software Development Ruby on Rails Algorithms Data Visualization
  1. The newsletter discusses a case of justice served in a #MeToo context, emphasizing the importance of identifying and addressing abnormal situations in professional environments.
  2. The community encourages creating safe spaces, advocating for victims of sexual violence, and providing support for legal processes.
  3. Recommendations are offered for joining women-centered Ruby communities, along with resources for building sustainable digital products and insights on improving team workflows.

My experience with the Google Foobar challenge

Technology Made Simple • 39 implied HN points • 27 Mar 22
🕹 Technology Coding Interviews Challenges Algorithms Google
  1. Google Foobar challenge consists of multiple levels and is invite-only, offering a chance for an onsite interview at Google.
  2. The challenge is designed like an infiltration story with lengthy, complex questions that require googling concepts and filtering out irrelevant information to solve.
  3. Passing the first 3 levels is relatively easier, but the final 2 stages demand specific knowledge of high-level concepts and a well-thought-out game plan for success.

[Solution]Problem 30: Find Distance to nearest Exit[Google]

Technology Made Simple • 39 implied HN points • 25 Mar 22
🕹 Technology Programming Algorithms Graphs
  1. Google coding challenges can be tricky and often require exploring optimal solutions beyond the obvious
  2. When solving problems involving distances in grids, consider using the concept of Manhattan Distance and graph structures to represent relationships between objects
  3. Choosing the best graph traversal algorithm is crucial; in cases like this problem where distances are equal and not weighted, BFS can be a simpler and more suitable choice compared to more complex algorithms like DFS
Get a weekly roundup of the best Substack posts, by hacker news affinity:

How Algorithms Exploit Laziness[Technique Tuesdays]

Technology Made Simple • 19 implied HN points • 16 Nov 22
🕹 Technology Algorithms Performance Coding
  1. Lazy evaluation in programming delays evaluation until the value is needed, which helps save computational resources and optimize performance.
  2. Partial evaluation allows quicker calculations by finding the first false value in a series of boolean operations, speeding up the process.
  3. Just-in-time compilation in computing involves compiling code at runtime, reducing strain on the system by loading only necessary parts, like in video games with large maps.

[Solution]Problem 26: Remove K digits to create smallest number[Microsoft]

Technology Made Simple • 39 implied HN points • 24 Feb 22
🕹 Technology Coding Problem Solving Algorithms Programming
  1. Given a non-negative integer as a string, you can create the smallest number by removing k digits strategically.
  2. For strings with digits sorted in descending order, removing the first k elements generates the smallest number.
  3. It's important to analyze patterns and consider removing significant digits in order to solve tricky problems like creating the smallest number by removing k digits.

Newsletter #2: Certain Randomness

Decoding Coding • 19 implied HN points • 09 Feb 23
🕹 Technology Computer Science Algorithms Cryptography Machine Learning Randomness
  1. Random numbers are important in computer science for things like cryptography, simulations, and game mechanics. They help create unpredictability and realism in these applications.
  2. There are two main types of random number generators: True Random Number Generators (TRNGs) that use real-world entropy, and Pseudo Random Number Generators (PRNGs) that produce predictable outcomes based on a starting value.
  3. Algorithms like Linear Congruential Generators (LCGs) and Mersenne Twister are commonly used for generating pseudo-random numbers in various applications due to their efficiency and quality.

Terms of Engagement

Cybernetic Forests • 39 implied HN points • 20 Feb 22
🕹 Technology Social media Algorithms Communication Design Digital Culture
  1. Communication requires good transmission and reception; without care on either end, hurt can result.
  2. Play and playfulness emerge from safety and shared agreement; the absence of play can lead to authoritarianism and fear.
  3. Social media structures can breed algorithmic indifference, filtering out personal content and hindering meaningful communication.

The uniformity measure

Fileforma Research • 1 HN point • 22 Jun 24
🕹 Technology Data Analysis Compression Algorithms Customization
  1. Neuralink's Compression Challenge requires beating ZIP at compressing audio files, revealing unexpected complexities in brain data compression
  2. Claude Shannon's use of logarithms in measuring entropy lacks proof, highlighting the need for alternative entropy measures like the uniformity measure
  3. The proposed uniformity measure offers a way to calculate a sample's proximity to a uniform distribution, providing a new method for entropy measurement

An Intro to Finite State Machines[Math Monday]

Technology Made Simple • 19 implied HN points • 08 Aug 22
🕹 Technology Programming Software Engineering Computer Science Tutoring Algorithms
  1. Finite State Machines (FSMs) are like directed graphs that help in understanding the flow of a program. Nodes represent states and edges show reachable states.
  2. FSMs are useful for filtering input based on rules and when a system is defined by a set of conditions, like in Regex applications.
  3. Mastering FSMs involves patience, practice, and hands-on coding of theoretical concepts to understand and implement them effectively.

Is your bucket leaky?

Freelance Footprints • 8 HN points • 20 Feb 24
🕹 Technology Algorithms Web Development Data Structures Networking Software Engineering
  1. The leaky bucket algorithm helps manage the rate of requests a web application can handle. It uses the idea of a bucket that can fill up and overflow if too many requests come in at once.
  2. In this algorithm, there are two key settings: the maximum number of requests allowed at a time and the rate at which requests are processed. This controls how quickly requests are dealt with and prevents overload.
  3. The leaky bucket algorithm is widely used in tech, such as by companies like SeatGeek for their waiting room systems, to ensure smooth user experiences without exceeding server limits.

Problem 2: Find all occurrences of Substring Solution [Microsoft] (Example of Solutions in Paid Version)

Technology Made Simple • 39 implied HN points • 23 Aug 21
🕹 Technology Coding Algorithms Hashing Optimization
  1. When solving problems, start with a simple solution even if it's not optimal. It's better to have a working brute-force solution than no solution at all.
  2. Optimizing code involves identifying and eliminating redundant parts. For instance, in string matching problems, consider using techniques like hashing to improve efficiency.
  3. The Rabin-Karp algorithm is a rolling hash function used for string searching. It involves using hashes to compare substrings efficiently, reducing false positives and improving overall performance.

[Solution]Problem 44: Longest Substring Without Repeating Characters (Meta / Facebook)

Technology Made Simple • 19 implied HN points • 01 Jul 22
🕹 Technology Programming Algorithms Data Structures Web Development
  1. The problem discussed is about finding the length of the longest substring without repeating characters.
  2. Approaching a coding problem by carefully considering the data structures to use, like dictionaries and sets, can be crucial in developing an efficient solution.
  3. Building a clear path to figure out the start and end points of the substring can lead to a more organized and effective algorithm implementation.

How to Spot Greedy Algorithms[Techinque Tuesdays]

Technology Made Simple • 19 implied HN points • 22 Jun 22
🕹 Technology Algorithms Coding Math AI Interviews
  1. Greedy algorithms make decisions based on immediate benefit, without looking ahead to future consequences.
  2. To identify a greedy algorithm, look for problems that can be broken into sub-problems, where the optimal solution of each sub-problem contributes to the overall optimal solution.
  3. Improving at recognizing greedy algorithms requires practice and analysis of problems to refine your intuition.

[Solution]Problem 42: Length of the longest subarray where all its elements are distinct (Microsoft)

Technology Made Simple • 19 implied HN points • 17 Jun 22
🕹 Technology Math Combinatorics Data Structures Algorithms
  1. When faced with a problem involving combinatorics, taking the time to read and analyze the question can provide crucial insights for a more efficient solving approach
  2. In the context of building max heaps from a list of integers, understanding the structure of heaps as complete binary trees allows for simplification of the problem into calculating combinations and values for left and right subtrees
  3. Calculating the values for the left subtree, such as height and number of nodes, can lead to a shift in the coding task complexity from generating heaps to conducting combinatorics

AprilTags: Why Robotics Invented Its Own QR Code

Luminotes • 7 implied HN points • 09 Feb 24
🕹 Technology Robotics Computer Vision Algorithms Open Source Image Processing
  1. AprilTags are similar to QR codes but are used as fiducial markers in robotics for localization purposes.
  2. AprilTags, created by the reputable robotics lab April, enable systems to localize features in 6 degrees of freedom using a single image.
  3. AprilTags differ from QR codes as they are designed for easy detection in low resolution, unevenly lit, or cluttered images and can detect multiple tags.

[Solution]Problem 39: Find the Celebrity[Pintrest]

Technology Made Simple • 19 implied HN points • 27 May 22
🕹 Technology Math Logic Coding Algorithms
  1. The problem involves finding a celebrity at a party who everyone knows, but who doesn't know anyone in return. A brute force approach of comparing every pair of people at the party can be used, but it is slow with O(N^2) complexity.
  2. It is essential to analyze why a solution is inefficient to brainstorm and develop an optimal solution efficiently. By utilizing constraints given in the problem, like the knowledge asymmetry between the celebrity and others, the time and space complexity can be significantly reduced to O(N) and O(1) respectively.
  3. In problem-solving, understanding and applying constraints effectively can lead to substantial improvements in both time and space complexity, making solutions more efficient and optimal.

[Solution]Problem 31:Maxium Rainwater Trapping[Microsoft]

Technology Made Simple • 19 implied HN points • 01 Apr 22
🕹 Technology Coding Problem Solving Algorithms Tooling
  1. Understanding the problem thoroughly is essential in tackling difficult coding challenges. Break down the problem into smaller components and focus on each step.
  2. Identifying patterns and creating systems can help simplify complex problems. Mathematics can be a powerful tool in problem-solving and coding interviews.
  3. Utilizing techniques like the two-pointer approach can be incredibly helpful in optimizing solutions and acing technical interviews.

Why Math Mondays

Technology Made Simple • 19 implied HN points • 14 Mar 22
🚌 Education Math Interview Preparation Knowledge Data Structures Algorithms
  1. Understanding the importance of Math in preparation can help with solving problems better.
  2. Knowledge about subjects, problem interpretation, and connections between topics are crucial in problem-solving.
  3. Math Mondays aim to show how mathematical knowledge can enhance problem-solving skills and help make connections between different concepts.

Data Science Weekly - Issue 455

Data Science Weekly Newsletter • 19 implied HN points • 11 Aug 22
🕹 Technology Data science AI Machine Learning Data Engineering Algorithms
  1. Data professionals spend a lot of time checking data quality, which costs companies a lot of money every year. Poor data quality can affect a company's revenue significantly.
  2. Understanding how AI models behave is important for data scientists. They need to develop good mental models to train and work effectively with these systems.
  3. Vector search is becoming popular in retail for improving various aspects like revenue and customer satisfaction. It helps teams make better use of their data.

4/6/22 China Mandates Recommendation Algorithms To Be Able To Be Turned Off

Tech Buzz China Insider • 19 implied HN points • 07 Apr 22
🕹 Technology Regulations Algorithms Business impact User Experience Ecommerce
  1. China mandated that recommendation algorithms must have an option to be disabled, becoming a global leader in regulating emerging technologies.
  2. Turning off recommendation algorithms can enhance user experience, but the impact on businesses varies depending on their reliance on algorithms.
  3. While many users express interest in disabling recommendation algorithms, the actual business impact may not be significant as users may struggle to find and use the option.

[Solution]Problem 22: Positive Pairs meeting conditions[Jane Street]

Technology Made Simple • 19 implied HN points • 27 Jan 22
🕹 Technology Coding Math Optimization Algorithms
  1. The problem involves finding pairs of positive integers that satisfy specific conditions involving addition and XOR operations.
  2. Understanding binary representation and logical operators like XOR can lead to more optimal solutions for certain problems.
  3. Mathematical reasoning and logical analysis can help in optimizing solutions and reducing time complexity, especially when dealing with binary operations.

[Solution]Problem 18: Pack Words on Board [Google]

Technology Made Simple • 19 implied HN points • 30 Dec 21
🕹 Technology Coding Algorithms
  1. The problem involves finding the maximum number of words that can be constructed from a given dictionary and a matrix of random letters.
  2. The solution to this problem involves using backtracking, a recursive algorithmic technique that incrementally builds a solution while adhering to constraints.
  3. When solving such problems, it is important to consider traversing the matrix, ensuring that letters are adjacent vertically and horizontally, and not diagonally.

[Solution]Mastermind Code Decoding [Facebook]

Technology Made Simple • 19 implied HN points • 10 Dec 21
🕹 Technology Algorithms Programming Interviewing Optimization
  1. The problem involves a two-player game called Mastermind where one player must guess the other player's secret code based on feedback provided after each guess.
  2. Implementing a brute force solution as a first step can provide a structured approach, help avoid freezing up during interviews, give hints for optimization, and showcase organization.
  3. Optimizing brute force solutions involves narrowing down the pool of possible solutions based on the constraints provided in the problem, which can significantly reduce the search space.

Problem 15: Mastermind Code Decoding [Facebook]

Technology Made Simple • 19 implied HN points • 09 Dec 21
🕹 Technology Coding Algorithms Problem Solving
  1. Mastermind is a two-player game where one player guesses the secret code of the other player.
  2. In the game, the first player guesses a number, and the response indicates how many digits were correctly placed in the secret code.
  3. An algorithm is needed to determine if a given sequence of guesses and their scores can be produced by a particular secret code.

[Solution]Problem 14: Smallest Closed Interval [Google]

Technology Made Simple • 19 implied HN points • 03 Dec 21
🕹 Technology Coding Algorithms Programming
  1. Given a set of closed intervals, find the smallest set of numbers that covers all the intervals, allowing for multiple smallest sets to be returned.
  2. Defining intersecting intervals involves comparing the lower bound of one interval with the upper bound of another to see if they intersect.
  3. Tighten the bounds by picking the smallest intersection between two intervals, considering different kinds of intersections.

[Solution]Problem 12: Group Shifted Strings [Facebook]

Technology Made Simple • 19 implied HN points • 05 Nov 21
🕹 Technology Coding Programming Problem Solving Algorithms Software Development
  1. Given an array of strings, group them based on being shifted versions of each other by finding the difference in characters.
  2. Implementing a hashset can efficiently group strings by their difference strings for quick retrieval.
  3. Creating helper functions and structuring your solution neatly can showcase your organization and problem-solving skills.

[Solution]Problem 11: Counts nodes in Complete Binary Tree [Amazon]

Technology Made Simple • 19 implied HN points • 31 Oct 21
🕹 Technology Coding Binary Trees Algorithms Math Web
  1. Given a complete binary tree, counting the number of nodes can be done faster than O(n) by leveraging the properties of complete binary trees.
  2. For a full binary tree, the number of nodes can be calculated using a simple formula of 2^(depth + 1) - 1, which allows for efficient calculation in O(h) operations.
  3. By recognizing the characteristics of complete binary trees, such as the presence of full sub-trees, one can strategically cut down recursion and analyze only half of the tree at each depth for faster computation.

[Solution]Problem 8: Maximum Stock Profit[Facebook]

Technology Made Simple • 19 implied HN points • 08 Oct 21
🕹 Technology Coding Algorithms Stock Markets
  1. The problem involves finding the maximum profit from buying and selling a stock once based on historical prices.
  2. The initial brute force solution checks all possible pairs of buy and sell points, but we can optimize this approach.
  3. Analyzing the given context shows that we have all price data up front, and we only need to optimize a single trade, not overall profit.

[Solution]Problem 7: Merge Binary Trees [Salesforce]

Technology Made Simple • 19 implied HN points • 01 Oct 21
🕹 Technology Programming Interviews Recursion Algorithms Coding
  1. When solving tree problems recursively, finding the base cases first helps in organizing the solution and demonstrates a structured problem-solving approach to the interviewer.
  2. Merging two binary trees involves summing up corresponding nodes from input trees and creating a new tree based on the sum values.
  3. The time complexity of merging two binary trees recursively is O(m+n), where m and n are the number of nodes in each of the input trees.

How to improve social media - Part I

Optimally Irrational • 4 implied HN points • 24 Jan 24
🕹 Technology Social media Incentives Consensus Algorithms
  1. Improving social media platforms can lead to more constructive and reasoned discussions by favoring consensual views
  2. Social media is like a game of status where users compete for social recognition through likes and reposts
  3. Different social media platforms have unique cultures of interaction shaped by social norms which influence user behavior

Afternoon project: JPEG DCT text lossifizer

lcamtuf’s thing • 3 HN points • 17 Mar 24
🕹 Technology Algorithms Compression Text Analysis
  1. Using discrete cosine transform (DCT) for lossy compression can be applied to text data by converting it into frequency coefficients, quantizing them, and then reversing the process to obtain reduced-fidelity text.
  2. Mapping text data to numerical representation through a perceptual character table, rather than ASCII, can significantly improve readability even in high quantization settings.
  3. In text compression, focusing on higher-frequency components is crucial for maintaining readability, unlike image compression where higher-frequency components are reduced more aggressively.