z3
adventofcode
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z3 | adventofcode | |
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28 | 55 | |
9,627 | 20 | |
1.4% | - | |
9.9 | 7.8 | |
5 days ago | 3 months ago | |
C++ | Elixir | |
GNU General Public License v3.0 or later | - |
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Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
z3
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Lean4 helped Terence Tao discover a small bug in his recent paper
Code correctness is a lost art. I requirement to think in abstractions is what scares a lot of devs to avoid it. The higher abstraction language (formal specs) focus on a dedicated language to describe code, whereas lower abstractions (code contracts) basically replace validation logic with a better model.
C# once had Code Contracts[1]; a simple yet powerful way to make formal specifications. The contracts was checked at compile time using the Z3 SMT solver[2]. It was unfortunately deprecated after a few years[3] and once removed from the .NET Runtime it was declared dead.
The closest thing C# now have is probably Dafny[4] while the C# dev guys still try to figure out how to implement it directly in the language[5].
[1] https://www.microsoft.com/en-us/research/project/code-contra...
[2] https://github.com/Z3Prover/z3
[3] https://github.com/microsoft/CodeContracts
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Programming Languages Going Above and Beyond
I believe, Nim also has this functionality, although, it uses the [0]Z3Prover tool with a nim frontend [1]"DrNim" for proving.
- Modern SAT solvers: fast, neat and underused (2018)
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If You've Got Enough Money, It's All 'Lawful'
Don't get me wrong, there are times when Microsoft got it right the first time that was technically far superior to their competitors. Windows IOCP was theoretically capable of doing C10K as far back in 1994-95 when there wasn't any hardware support yet and UNIX world was bickering over how to do asynchronous I/O. Years later POSIX came up with select which was a shoddy little shit in comparison. Linux caved in finally only as recently as 2019 and implemented io_uring. Microsoft research has contributed some very interesting things to computer science like Z3 SAT solver and in collaboration with INRIA made languages like F* and Low* for formal specification and verification. But all this dwarfs in comparison to all the harm they did.
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General mathematical expression analysis system
Other than that, you should look at Z3 which is pretty damn good at these sort of theorems/constraints.
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-🎄- 2022 Day 21 Solutions -🎄-
In the end I used Z3 Julia bindings instead. The hardest part was to get the result back from it, because I kept running into assertion violations from inside Z3
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The Little Prover
> And you propose me instead to go and reverse engineer library Js code which I am not that proficient in, and rewrite all code in Java instead?..
Yes, rather than demand others cater to your whims, frankly.
Do you realise how hypocritical it sounds to complain that you are not proficient in Javascript, when others might not be proficient in ?
Go use Z3 if you need a prover in C++ (or Java), its far more robust (provided its the type you're after) than someones 700 LoC JavaScript implementation.
- Ask HN: When you code at work, how do you code in your time off?
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AMA: We are the creators of The Puzzler Hunt. Ask us anything!
My open-source project https://github.com/obijywk/grilops (excuse the shameless plug) can help when creating Nikoli-style grid logic puzzles, and we used it during the development of Ents, Resolution, and Missing Pieces (and to check uniqueness of Digital Gaming solutions). The constraint solver library it depends on, https://github.com/Z3Prover/z3 from Microsoft Research, is also very useful on its own, and we used it to help with the creation of Art Gallery and Global Shipping Crisis. Dennis Yurichev's SAT/SMT By Example is an extensive resource for learning how to use these kinds of tools to solve all sorts of problems, including puzzle solving.
- Make formal verification and provably correct software practical and mainstream
adventofcode
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-❄️- 2023 Day 10 Solutions -❄️-
Part one went fairly fast, but spent quite some time on getting part two right. I settled on the approach of just iterating over the grid and using a boolean to see if I had to count elements or not. However, I had some issues figuring out when to swap, this post by /u/rogual helped me figure it out. After that I lost quite some time on an error that only occurred with my input, not with the example input. It turned out that my loop (which I take form my p1 solution) didn't include the start node, which caused all sorts of counting issues.
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-❄️- 2023 Day 4 Solutions -❄️-
[Language: Elixir] https://github.com/mathsaey/adventofcode/blob/master/lib/2023/4.ex
- -🎄- 2022 Day 25 Solutions -🎄-
- -🎄- 2022 Day 24 Solutions -🎄-
- -🎄- 2022 Day 23 Solutions -🎄-
- -🎄- 2022 Day 22 Solutions -🎄-
- -🎄- 2022 Day 21 Solutions -🎄-
- -🎄- 2022 Day 20 Solutions -🎄-
- -🎄- 2022 Day 19 Solutions -🎄-
- -🎄- 2022 Day 18 Solutions -🎄-
What are some alternatives?
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AdventOfCode2021 - Advent of code 2021
adventofcode - Advent of Code solutions of 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 and 2023 in Scala
magmide - A dependently-typed proof language intended to make provably correct bare metal code possible for working software engineers.
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adventofcode - Answers to Advent of Code
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