CheckiO is a game where you code in Python or JavaScript.Progress in the game by solving code challenges and compete for the most elegant and creative solutions
Joined October 2010
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267 Photos and videos
Feb 5
buff.ly/scJR1Pv Given the initial positions where the members of the group are seated, determine the minimum number of exchanges between students sitting in neighboring chairs so that each member of the group of friends sits in front of another member of the group.
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Feb 3
buff.ly/ThErYA8 Learn how to create a Django project and app in clear, guided steps. Use it as a reference for any future Django project and tutorial you’ll work on.
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Jan 31
buff.ly/RZhRlDo This week's digest streamlines your workflow, from a rock-solid Django setup to mastering type hinting for decorators and the power of Enums for constants. We conclude with a logic-heavy mission to reorganize cafeteria seating with minimal student swaps.
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Jan 29
buff.ly/DcKR7W6 This function should take a non-negative integer as an input and return the factorial of that number.
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Jan 27
buff.ly/MVxWBwZ Testing your code is important, but not just for correctness also for performance. One approach is to check performance degradation as data sizes go up, also known as Big-O scaling.
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Jan 24
buff.ly/0TZOFSE This week's digest explores the depths of code quality, from detecting performance regressions with Big-O tests to mastering recursive structural pattern matching. We also recap the year with a Django quiz and challenge you to calculate the factorial.
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Jan 22
buff.ly/lW5WAw1 Given a string that represents the column title as appears in an Excel sheet, return its corresponding column number.
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Jan 20
buff.ly/oaYGggn Explore high-level architectural shifts toward multi-agent orchestration and protocol standardization.
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Jan 17
buff.ly/JcPxL63 Dive into Python's future with 2026 project roadmaps, master the elegance of decorators and context managers, and explore the cutting edge of agentic AI. Plus, solve a classic coordinate mission: converting Excel column letters to numbers.
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Jan 15
buff.ly/8jANSmx Identify whether a given integer is positive, negative, or zero and return a respective string: "positive", "negative" or "zero".
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Jan 13
buff.ly/KiIIQaQ This opinion piece argues that there is one skill that separates senior engineers from everyone else. It isn’t technical. It’s the ability to take ambiguous problems and make them concrete.
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Jan 10
buff.ly/8S21vED This week's digest explores the path to mastery, defining what truly makes a developer senior beyond years of experience. We also break down the SOLID principles for better Python design and dive deep into the internals of dataclasses.
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Jan 6
buff.ly/IXAyvRy Simon talks about what it means to be a responsible developer in the age of AI tooling. In short: you’re still responsible for checking the code works regardless of who/what wrote it.
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Jan 3
buff.ly/ZwDYWqO This week's digest explores the pursuit of mastery, featuring Simon Willison's take on verifying code correctness, the importance of embracing whitespace for readability, and a guide to essential Python skills.
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Jan 1
buff.ly/Q9OVPsL Check if the given year is leap year. A year is a leap year if it is divisible by 4, except for end-of-century years which must be divisible by 400.
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30 Dec 2025
buff.ly/rGoy1rm Reuven has been freelancing for a long time, including both working and teaching Python and pandas. This post summarizes some of the key things he’s learned in the last 30 years.
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27 Dec 2025
buff.ly/vngweSa This week's digest explores technical efficiency and career wisdom, starting with an overview of Python module compression. We dive into thirty years of business lessons from Reuven Lerner and test your knowledge of inner functions with a specialized quiz.
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25 Dec 2025
buff.ly/7zyoaPB This week's digest explores high-performance data manipulation, featuring a comparison of Pandas, Polars, and DuckDB. We also cover practical text formatting by learning how to wrap text and introduce the theoretical foundation of quantum computing.
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23 Dec 2025
buff.ly/d0jOCKq Commit to mastering Python and TypeScript this year with CheckIO and secure an immediate 30% discount on your full 2026 annual subscription!
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20 Dec 2025
buff.ly/7zyoaPB Commit to mastering Python and TypeScript this year with CheckIO and secure an immediate 30% discount on your full 2026 annual subscription!
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