# Puzzle Published articles for Puzzle. This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## Solving a Double-Sided Wooden Puzzle with Coordinate Systems and Search Pruning DevFeed: [Solving a Double-Sided Wooden Puzzle with Coordinate Systems and Search Pruning]() Original publisher: [Read original article]() Author: Khan Academy Published: 2015-07-06T22:00:00Z Content type: article Language: en Sources: [Khan Academy]() Topics: [Development](), [Math and Logic]() Tags: [dev](), [engineering](), [logic](), [news](), [program](), [puzzle](), [puzzles](), [web-frontend]() ### AI overview John Sullivan describes how five Khan Academy developers wrote solvers for a double-sided wooden puzzle. The article covers representing piece positions, handling rotations and reflections, and pruning the search space to improve placement search. ### Source excerpt By John Sullivan Last week a mysterious double-sided puzzle appeared at Khan Academy. To solve the puzzle you ... Read more ## Squingle Arcade Is Available Now For Free On PC VR DevFeed: [Squingle Arcade Is Available Now For Free On PC VR]() Original publisher: [Read original article]() Author: Mike Johnson Published: 2026-09-10T00:14:39Z Content type: news Language: en Sources: [UploadVR]() Topics: [arcade](), [Mazes](), [pc]() Tags: [free](), [leaderboards](), [multiplayer](), [orbs](), [pc](), [puzzle](), [vr-gaming]() ### AI overview Squingle Arcade, a free-to-play quickplay version of the fluid-maze puzzle game Squingle, is now available on SteamVR and Quest. It includes more than 60 levels, asynchronous multiplayer, ghost racing, leaderboards, and scalable mazes. ### Source excerpt Squingle Arcade, the follow up to the original fluid-maze-navigating puzzle game Squingle, is out now for PC VR. ## Reverse-engineer an ASIC from its chip layout DevFeed: [Reverse-engineer an ASIC from its chip layout]() Original publisher: [Read original article]() Author: Anish Singhani Published: 2026-08-05T00:00:00Z Content type: article Language: en Sources: [Jane Street]() Topics: [Hardware](), [Reverse Engineering](), [Verilog](), [Routing (disambiguation)](), [Code]() Tags: [code](), [design-automation](), [engineering](), [hardware](), [puzzle](), [reverse-engineering](), [routing](), [signal]() ### AI overview Jane Street presents a puzzle that challenges readers to reverse-engineer an ASIC from its physical chip layout, recover the underlying netlist, determine the circuit's purpose, and derive a final answer from its output. ### Source excerpt Earlier this year we published a puzzle that handed you a complete neural network and asked you to figure out what it did. The response was great, so we've made another one! This time, we're going much deeper down the tech stack. For this puzzle we've designed a chip, but we're only giving you the layout. A crash course in how chips get made Modern chips start life as code. ## Gamification 2.0. Beyond Points and Badges: Designing for Players, Not Metrics. Chapter 5: Implementation DevFeed: [Gamification 2.0. Beyond Points and Badges: Designing for Players, Not Metrics. Chapter 5: Implementation]() Original publisher: [Read original article]() Author: Montgomery Singman Published: 2026-06-09T03:26:13Z Content type: tutorial Language: en Sources: [UX Magazine]() Topics: [implementation](), [User experience (UX)](), [App]() Tags: [app](), [building](), [complex-systems](), [core](), [creative](), [design](), [expression](), [games](), [implementation](), [interface](), [leaderboard](), [loops](), [management](), [multiplayer](), [puzzle](), [rpg](), [sandbox](), [simulation](), [strategy](), [ux]() ### AI overview This chapter presents a practical framework for implementing Gamification 2.0. It recommends choosing a dominant game genre that matches an app's core activities, aligning that genre with user psychology, and designing satisfying intrinsic interaction loops before adding points, badges, or other extrinsic rewards. ### Source excerpt Part 5 of the "Gamification Series." A framework for developers: from theory to practice Everything I've outlined so far is meaningless if you can't apply it. So let me give you a practical framework for actually implementing Gamification 2.0. Step 1: Stop copying mechanics; choose a genre Your first question isn't "What gamification mechanics should The post Gamification 2.0. Beyond Points and Badges: Designing for Players, Not Metrics. Chapter 5: Implementation appeared first on UX Magazine. ## Reverse-engineering a neural network puzzle with mechanistic interpretability DevFeed: [Reverse-engineering a neural network puzzle with mechanistic interpretability]() Original publisher: [Read original article]() Author: Ricson Cheng Published: 2026-02-24T00:00:00Z Content type: tutorial Language: en Sources: [Jane Street]() Topics: [Neural Network](), [Machine learning](), [PyTorch]() Tags: [capture](), [ml](), [models](), [neural](), [puzzle](), [pytorch](), [research]() ### AI overview This article explains a Jane Street machine-learning puzzle in which solvers receive a neural network specification, including its weights, and must determine what the network does. It describes why ordinary brute-force approaches fail and presents a solver's reverse-engineering process using mechanistic interpretability. ### Source excerpt A lot of "capture-the-flag" style ML puzzles give you a black box neural net, and your job is to figure out what it does. When we were thinking of creating our own ML puzzle early last year, we wanted to do something a little different. We thought it'd be neat to give users a complete specification of the neural net, weights and all. They would then be forced to use the tools of mechanistic interpretability to reverse engineer the network--which is a situation we sometimes find ourselves facing in our own research, when trying to interpret features of complex models. ## Whodunit: LLM Murder Mysteries DevFeed: [Whodunit: LLM Murder Mysteries]() Original publisher: [Read original article]() Author: James Heller Published: 2025-08-26T07:00:00Z Content type: article Language: en Sources: [Apartment 304]() Topics: [LLM Techniques](), [Go Language]() Tags: [ai-authored](), [apartment-304](), [custom-software-solutions](), [devops](), [devops-engineer](), [go](), [golang](), [language-models](), [large-language-models](), [llm](), [logic](), [models](), [puzzle](), [puzzles](), [software-architecture](), [software-development](), [software-engineer](), [strategies](), [test]() ### AI overview This article describes building Whodunit, a low-tech murder-mystery game whose mysteries are written with large language models. It discusses developing a mental model for calling LLMs, testing LLM services and Go libraries, improving logical soundness through trial and error, and managing unreliable LLM APIs. ### Source excerpt Can Large Language Models write engaging mysteries? Find out in this week's episode of "Whodunit?" ## Developing an Internal Tool for Our Puzzle Editor DevFeed: [Developing an Internal Tool for Our Puzzle Editor]() Original publisher: [Read original article]() Author: The NYT Open Team Published: 2025-06-02T15:54:44Z Content type: article Language: en Sources: [New York Times]() Topics: [dashboards](), [Data Management](), [interface](), [payload](), [Testing](), [Tool]() Tags: [code](), [dashboard](), [data-management](), [developing](), [interface](), [internal-tools](), [payload](), [puzzle](), [testing](), [tool](), [web-development](), [workflow]() ### AI overview The article describes how The New York Times developed the Connections Reference Dashboard, an internal tool for managing puzzle data and supporting the Connections editor's workflow. It explains the tool's interface, handling of changing puzzle data, search capabilities, and reduction of manual cross-referencing steps. ### Source excerpt How we developed a dashboard tool created to help ease the workflow of managing puzzles for our Connections editor.Illustration by Su Yun Song By Shafik Quoraishee and Wyna Liu In the game Connections, every puzzle is a meticulously crafted challenge designed to captivate our audience and spark intellectual curiosity. Developing these puzzles can sometimes be a time consuming and intricate task. Each puzzle requires planning, beginning with conceptualizing fresh categories and plausible misleads, followed by testing the combinations for balance and solvability, and concluding with refinement and publication-ready formatting. The process requires both creativity and quality control. Wyna Liu, the editor of Connections has the responsibility of constructing and reviewing multiple puzzles spanning various dates, ensuring that each board remains consistent, fresh and challenging to our puzzle solvers. This is a challenging endeavor where there isn't much room for error. In order to address the challenge, we developed the Connections Reference Dashboard -- an in company tool aimed at streamlining data management while providing the puzzle editor with an intuitive, aesthetically pleasing interface that enhances the daily workflow. There were two considerations in developing this tool. Firstly was technical work in handling a dynamically changing payload of puzzle data. We wanted to create a rich and visually resonating interface that was easy to navigate and gave a bit of the feel of the Connections game itself. Therefore, everything from the board results to the search interface was designed with these ergonomics in mind. We wanted to create a level of tactility to the tool which was reminiscent of and which reduced the number of manual steps needed to cross reference both categories and words in individual boards. The primary functionality that Wyna was after was the ability to quickly identify words that have appeared in previous Connections boards, as well as their con ## Advent of Code 2024 in pure SQL DevFeed: [Advent of Code 2024 in pure SQL]() Original publisher: [Read original article]() Author: Thomas Neumann (noreply@blogger.com) Published: 2024-12-27T16:57:00Z Content type: article Language: en Sources: [Database Architects]() Topics: [SQL](), [Advent of Code](), [Algorithms](), [Programming](), [Graphs]() Tags: [advent-of-code](), [algorithm](), [duckdb](), [parsing](), [postgres](), [puzzle](), [recursive-sql](), [sql]() ### AI overview The author describes solving every Advent of Code 2024 problem in pure SQL. Small-scale traversals were practical and sometimes pleasant, while larger recursive queries could be inefficient and require more than 200 GB of memory. The experience suggests that recursive SQL would benefit from mechanisms for updating state and supporting more complex control flow. ### Source excerpt On a whim I decided to do this years advent of code in pure SQL. That was an interesting experience that I can recommend to everybody because it forces you to think differently about the problems. And I can report that it was possible to solve every problem in pure SQL. In many cases SQL was actually surprisingly pleasant to use. The full solution for day 11 (including the puzzle input) is shown below: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30with recursive aoc10_input(i) as (select ' 89010123 78121874 87430965 96549874 45678903 32019012 01329801 10456732 '), lines(y,line) as ( select 0, substr(i,1,position(E'\n' in i)-1), substr(i,position(E'\n' in i)+1) from aoc10_input union all select y+1,substr(r,1,position(E'\n' in r)-1), substr(r,position(E'\n' in r)+1) from lines l(y,l,r) where position(E'\n' in r)>0 ), field(x,y,v) as ( select x,y,ascii(substr(line,x::integer,1))-48 from (select * from lines l where line<>'') s, lateral generate_series(1,length(line)) g(x) ), paths(x,y,v,sx,sy) as ( select x,y,9,x,y from field where v = 9 union all select f.x,f.y,f.v,p.sx,p.sy from field f, paths p where f.v=p.v-1 and ((f.x=p.x and abs(f.y-p.y)=1) or (f.y=p.y and abs(f.x-p.x)=1)) and p.v>0), results as (select * from paths where v=0), part1 as (select distinct * from results) select (select count(*) from part1) as part1, (select count(*) from results) as part2 Parsing the input is a bit painful in SQL, but it is not too bad. Lines 1-10 are simply the puzzle input, lines 11-17 split the input into individual lines, and lines 18-21 construct a 2D array from the input. The algorithm itself is pretty short, lines 22-27 perform a recursive traversal of the field, and lines 28-39 extract the puzzle answer from the traversal results. For this kind of small scale traversals SQL works just fine. Other days were more painful. Day 16 for example does conceptually a very similar traversal of a field, and it computes the minimal traversal distance ## Computing Percentages Easier DevFeed: [Computing Percentages Easier]() Original publisher: [Read original article]() Published: 2023-09-05T21:47:37Z Content type: tutorial Language: en Sources: [Jeremy Kun]() Topics: [math](), [Computing]() Tags: [approach](), [arithmetic](), [math](), [mathematics](), [numbers](), [puzzle](), [scaling]() ### AI overview A math tutorial explains mental percentage calculations using the fact that x% of y equals y% of x. It presents several approaches, including choosing the easier percentage, multiplying first and dividing by 100, scaling from 1%, and splitting the denominator. ### Source excerpt Problem: Compute 16% of 25 in your head. Solution: 16% of 25 is equivalent to 25% of 16, which is clearly 4. This is true for all numbers: $x\%$ of $y$ is always equal to $y\%$ of $x$. The first one is $\frac{x}{100} y$ and the second is $\frac{y}{100}x$, and because multiplication is commutative and associative, both are equal to $(x \cdot y) / 100$. You can pick the version that is easiest. ## The Secrets of Skellig DevFeed: [The Secrets of Skellig]() Original publisher: [Read original article]() Published: 2023-07-17T00:00:00Z Content type: release Language: en Sources: [Robin Ward]() Topics: [Game Development](), [Godot](), [blender](), [3D]() Tags: [blender](), [development](), [game](), [game-development](), [games](), [puzzle]() ### AI overview The author announces The Secrets of Skellig, a puzzle game inspired by crosswords, while noting that the project is currently on indefinite hold. The article describes learning Blender and Godot while developing the game primarily alone. ### Source excerpt Note: The Secrets of Skellig is on indefinite hold now while I work on other things. I've wanted to dip my feet back into game development for a while, and last year I decided to put my money where my mouth is. I resigned from my full time job at Discourse and pulled up a bunch of YouTube tutorials on Blender and Godot. It's been a ridiculous amount of fun, and I've learned so much about how modern 3D games are made. I'm finally ready to announce what I've been working on. It's a puzzle game, inspired by crosswords, called "The Secrets of Skellig." ## Writing a Sokoban Puzzle Game in JavaScript DevFeed: [Writing a Sokoban Puzzle Game in JavaScript]() Original publisher: [Read original article]() Author: hello@taniarascia.com Published: 2021-07-26T00:00:00Z Content type: tutorial Language: en Sources: [Tania Rascia]() Topics: [JavaScript](), [Code](), [Canvas](), [HTML5](), [Demo](), [Web Development]() Tags: [canvas](), [code](), [demo](), [game](), [games](), [graphics](), [html5](), [javascript](), [puzzle]() ### AI overview A tutorial describing the implementation of a Sokoban puzzle game in JavaScript. It explains the map representation, entity movement and pushing rules, recursive handling of multiple blocks, and rendering the game on an HTML5 canvas. ### Source excerpt So the other day, I made an implementation of a Sokoban puzzle game in JavaScript. Here's the source code and here's the demo. The game... ## Interesting Matlab puzzle DevFeed: [Interesting Matlab puzzle]() Original publisher: [Read original article]() Author: Yair Altman Published: 2019-03-31T10:15:06Z Content type: opinion Language: en Sources: [Undocumented Matlab]() Topics: [MATLAB](), [Parser](), [Parsing](), [Programming]() Tags: [analysis](), [medium-risk-of-breaking-in-future-versions](), [medium-risk-of-breaking-in-future-versions-undocumented-feature](), [parsing](), [programming](), [pure-matlab](), [puzzle](), [undocumented-feature]() ### AI overview This article presents a Matlab code puzzle about conditional operators, evaluation behavior, operand order, and parentheses. It invites readers to predict and then run the code, highlighting how the results provide insight into Matlab's parser. ### Source excerpt A simple Matlab puzzle that leads to interesting insight on Matlab's parser. The post Interesting Matlab puzzle appeared first on Undocumented Matlab. Related posts: Interesting Matlab puzzle - analysis Solution and analysis of a simple Matlab puzzle that leads to interesting insight on Matlab's parser. ... An interesting uitree utility ExploreStruct is a utility that shows how custom uitrees can be integrated in Matlab GUI... A couple of internal Matlab bugs and workarounds A couple of undocumented Matlab bugs have simple workarounds. ... Matlab DDE support Windows DDE is an unsupported and undocumented feature of Matlab, that can be used to improve the work-flow in the Windows environment... ## Kotlin-Java Interop Can Cause Recursive Property Calls DevFeed: [Kotlin-Java Interop Can Cause Recursive Property Calls]() Original publisher: [Read original article]() Author: info@jeroenmols.com (Jeroen Mols) Published: 2018-11-01T00:00:00Z Content type: tutorial Language: en Sources: [Jeroen Mols]() Topics: [Kotlin](), [Java](), [Android Studio]() Tags: [android-studio](), [blogs](), [java](), [kotlin](), [legacy](), [legacy-code](), [puzzle](), [recursion](), [stackoverflow]() ### AI overview This article explains how Kotlin-Java interop can cause a property access to call itself recursively when inheriting from a Java class. It examines the resulting bytecode and notes that Android Studio can warn about the recursion. ### Source excerpt Java interop is one of the best features of the Kotlin language, yet sometimes this also can cause unforeseen issues... Puzzle # Disclaimer, the example below is a consequence of legacy code and only serves to demonstrate a Kotlin puzzler. ## A Kotlin lambda syntax pitfall that prevents animation updates DevFeed: [A Kotlin lambda syntax pitfall that prevents animation updates]() Original publisher: [Read original article]() Author: info@jeroenmols.com (Jeroen Mols) Published: 2018-09-25T00:00:00Z Content type: tutorial Language: en Sources: [Jeroen Mols]() Topics: [Kotlin](), [Programming language](), [Programming]() Tags: [blogs](), [code](), [function](), [kotlin](), [lambda](), [programming-language](), [puzzle](), [syntax]() ### AI overview This Kotlin puzzle explains why a progress bar fails to animate: a lambda is registered instead of invoking the method that handles animation updates. Changing the syntax so the method is called fixes the behavior. ### Source excerpt Kotlin is an incredibly enjoyable, concise and powerful programming language. Yet sometimes also a bit confusing... Puzzle # Have a look at the simple class below. ## Advent of Code 2016 DevFeed: [Advent of Code 2016]() Original publisher: [Read original article]() Published: 2016-12-24T00:00:00Z Content type: tutorial Language: en Sources: [Peter Norvig]() Topics: [Advent of Code](), [Code Challenge](), [Jupyter Notebook](), [Code]() Tags: [advent-of-code](), [code](), [jupyter-notebook](), [puzzle](), [solutions](), [test]() ### AI overview Peter Norvig documents his solutions to the Advent of Code puzzles released from December 1 through December 25, 2016. The notebook includes preparation, utility functions, tests, and selected explanations of his solving approach. ### Source excerpt Solutions to the puzzle site. ## Advent of Code 2017 DevFeed: [Advent of Code 2017]() Original publisher: [Read original article]() Published: 2016-12-24T00:00:00Z Content type: article Language: en Sources: [Peter Norvig]() Topics: [Advent of Code](), [Code]() Tags: [2017](), [advent-of-code](), [code](), [puzzle](), [solutions]() ### AI overview A collection of solutions to the Advent of Code 2017 puzzle site. ### Source excerpt Solutions to the puzzle site. ## How Ada Lovelace solved problems DevFeed: [How Ada Lovelace solved problems]() Original publisher: [Read original article]() Author: Graham King Published: 2015-12-11T05:02:00Z Content type: article Language: en Sources: [Graham King]() Topics: [Ada](), [Mathematics]() Tags: [ideas](), [mathematics](), [problems](), [program](), [puzzle](), [solve]() ### AI overview This article recounts how Ada Lovelace worked on a mathematics problem related to the Analytical Engine and documented what is described as the first known computer program for calculating Bernoulli numbers. When she became stuck, she went horseback riding and expected the problem to become clearer later. ### Source excerpt Ada Lovelace: Debugging by horseback since 1843. ## Exploring Variations on the Cheryl's Birthday Logic Puzzle DevFeed: [Exploring Variations on the Cheryl's Birthday Logic Puzzle]() Original publisher: [Read original article]() Published: 2015-05-13T00:00:00Z Content type: article Language: en Sources: [Peter Norvig]() Topics: [Math and Logic](), [Code](), [function]() Tags: [code](), [exploration](), [function](), [logic](), [puzzle]() ### AI overview This notebook explores variations of the Cheryl's Birthday logic puzzle by using code to verify generated date lists, randomly construct new puzzles, measure solution outcomes, and introduce a new character named Eve. ### Source excerpt An extended exploration beyond the popular "Cheryl's Birthday" logic puzzle. ## Cheryl's Birthday (How to Solve It with Code) DevFeed: [Cheryl's Birthday (How to Solve It with Code)]() Original publisher: [Read original article]() Published: 2015-04-24T00:00:00Z Content type: tutorial Language: en Sources: [Peter Norvig]() Topics: [Programming](), [Python](), [Code](), [Math and Logic]() Tags: [code](), [computer](), [functions](), [how-to](), [logic](), [programming](), [puzzle](), [python]() ### AI overview A tutorial that solves the Cheryl's Birthday logic puzzle by translating its statements and possible dates into Python code. It explains how computational enumeration can verify the puzzle's conditions and support problem solving. ### Source excerpt A solution to the popular "Cheryl's Birthday" logic puzzle. ## How theoretical computer science explains the complexity of puzzle games DevFeed: [How theoretical computer science explains the complexity of puzzle games]() Original publisher: [Read original article]() Published: 2014-03-17T10:00:55Z Content type: opinion Language: en Sources: [Jeremy Kun]() Topics: [computational complexity](), [Algorithms, Complexity](), [Computer science](), [Algorithms](), [Mazes]() Tags: [algorithm](), [art-gallery-problem](), [bin-packing](), [board-games](), [computational-complexity](), [computer](), [computer-science](), [exp](), [game](), [games](), [games-on-graphs](), [graph-coloring](), [greedy-spiders](), [mario](), [nintendo](), [np](), [np-completeness](), [np-hard](), [pancake-flipping](), [pspace](), [puzzle](), [science](), [starcraft](), [video-games]() ### AI overview The article explains that NP-hardness in games describes worst-case computational complexity, not how difficult a game is for human players. It uses examples including Pokémon, Super Mario Bros., Candy Crush Saga, Pac-Man, Doom, Starcraft, Tetris, chess, checkers, and Go to discuss hardness results and practical algorithms. ### Source excerpt Two years ago, Erik Demaine and three other researchers published a fun paper to the arXiv proving that most incarnations of classic nintendo games are NP-hard. This includes almost every Super Mario Brothers, Donkey Kong, and Pokemon title. Back then I wrote a blog post summarizing the technical aspects of their work, and even gave a talk on it to a room full of curious undergraduate math majors. But while bad tech-writers tend to interpret NP-hard as "really really hard," the truth is more complicated. ## Python Puzzle Solutions DevFeed: [Python Puzzle Solutions]() Original publisher: [Read original article]() Published: 2013-10-31T17:47:00Z Content type: article Language: en Sources: [Allison Kaptur]() Topics: [Python](), [test](), [function]() Tags: [blog-post](), [puzzle](), [python](), [solutions]() ### AI overview The article clarifies the rules for a Python puzzle and discusses submitted solutions, including Jessica McKellar's stateful solution and a correction that it passes the order test. ### Source excerpt I really enjoyed seeing all the clever solutions to the python puzzle I posted. You're all very creative! Here's a discussion of the solutions I've seen, plus some clarifications. All spoilers are below the fold. First, clarifications. (These weren't always clear in the problem statement, particularly if you got the problem off of twitter, so award yourself full marks as desired.) Order doesn't matter "Order doesn't matter" means that the three-line version always returns False, and the semicolon version always returns True. You control only the contents of the lines Several people, including Pepijn De Vos, David Wolever, and diarmuidbourke suggested something like the following: 1 2 3 4 5 6 >>> """a; b; c""" == 'a; b; c' True >>> """a ... b ... c""" == 'a; b; c' False I'm being pedantic here, but I rule this cheating, since (a) each line has to be a valid python expression or statement, and a multi-line string literal is only one expression, and (b) the string """a; b; c""" is not the same as the string """a\nb\nc""". Solutions appear below the fold. Solutions! Jessica McKellar Jessica suggests the following solution: 1 2 3 4 5 6 7 8 9 10 11 12 13 >>> global a >>> a = a + "a" if "a" in globals() else "" >>> print(bool(len(a) % 3)) False >>> global a; a = a + "a" if "a" in globals() else ""; print(bool(len(a) % 3)) True >>> def my_function(): ... global a ... a = a + "a" if "a" in globals() else "" ... print(bool(len(a) % 3)) ... >>> my_function() True However, Jessica's solution fails the "order doesn't matter" test, and it is stateful: 1 2 3 4 >>> global a; a = a + "a" if "a" in globals() else ""; print(bool(len(a) % 3)) False >>> global a; a = a + "a" if "a" in globals() else ""; print(bool(len(a) % 3)) True Edit: As Jessica points out, I'm wrong here: her solution does pass the order test. She also notes that the restriction against state wasn't present in the blog post (and she didn't see the original tweet). Full credit to Jessica, then! Javier Novoa Cataño Ja ## A Python puzzle DevFeed: [A Python puzzle]() Original publisher: [Read original article]() Published: 2013-10-30T02:40:00Z Content type: article Language: en Sources: [Allison Kaptur]() Topics: [Python](), [Code](), [function]() Tags: [code](), [function](), [puzzle](), [python](), [rules](), [stateful]() ### AI overview A Python puzzle challenges readers to find three valid Python expressions that produce different results when run separately, on one line with semicolons, and inside a function. The solution must avoid introspection, dunder methods, order dependence, and stateful behavior. ### Source excerpt A couple of Hacker Schoolers were discussing an interesting corner of python today. We discovered a nice bit of trivia: there exist three lines of python code that display the following behavior: 1 2 3 4 5 6 7 8 9 10 11 12 >>> LINE_A >>> LINE_B >>> LINE_C False >>> LINE_A; LINE_B; LINE_C True >>> def my_function(): ... LINE_A ... LINE_B ... LINE_C >>> my_function() True What are the lines? Some ground rules: Introspection of any kind is cheating (e.g. noting the line number). No dunder (__foo__) methods allowed. Each line is a valid python expression. You can't rely on order: while the lines will always execute A -> B -> C, a complete solution behaves identically if e.g. the semicolon version happens before the separate-line version. No cheating with the function: e.g. you can't add a return unless you add it everywhere. Edit: And nothing stateful. For bonus points, code golf! My solution to this is 14 19 characters long, not counting whitespace. ## Java Puzzle: Square Root DevFeed: [Java Puzzle: Square Root]() Original publisher: [Read original article]() Author: Square Engineering Published: 2013-03-19T16:02:00Z Content type: article Language: en Sources: [Square Corner Blog](), [Square Corner Blog RSS Feed]() Topics: [Java](), [Algorithms](), [Programming]() Tags: [algorithms](), [code](), [engineering](), [java](), [jdk](), [puzzle]() ### AI overview A Java programming puzzle challenges readers to reach a call to SquareRoot.answer and calculate the square root of a huge number without directly inspecting it. The solution must be a separate Java file that runs with the security manager enabled on JDK 6 or 7, without using setAccessible or exploiting JDK vulnerabilities. ### Source excerpt Show your Java-fu by calculating the unknown. ## Date puzzle for starters DevFeed: [Date puzzle for starters]() Original publisher: [Read original article]() Author: Dimitri Fontaine PostgreSQL Major Contributor; Author Published: 2010-10-08T08:00:00Z Content type: article Language: en Sources: [Dimitri Fontaine]() Topics: [PostgreSQL](), [function](), [IRC]() Tags: [blog](), [exercise](), [function](), [postgresql](), [puzzle]() ### AI overview A PostgreSQL date puzzle explores how to identify the nth occurrence of a specified weekday within a month. The article discusses an unfinished function and leaves improvements--such as supporting multiple nth weekdays--as an exercise for readers. ### Source excerpt The PostgreSQL IRC channel is a good place to be, for all the very good help you can get there, because people are always wanting to remain helpful, because of the off-topics discussions sometime, or to get to talk with community core members. And to start up your day too. This morning's question started simple : "how can I check if today is the "first sunday fo the month". or "the second tuesday of the month" etc?" [Next page]()