diff --git a/rust/nth-prime/.exercism/config.json b/rust/nth-prime/.exercism/config.json new file mode 100644 index 0000000..57d36ce --- /dev/null +++ b/rust/nth-prime/.exercism/config.json @@ -0,0 +1,37 @@ +{ + "authors": [ + "sacherjj" + ], + "contributors": [ + "attilahorvath", + "cbzehner", + "coriolinus", + "cwhakes", + "eddyp", + "efx", + "ErikSchierboom", + "imbolc", + "lutostag", + "nfiles", + "petertseng", + "rofrol", + "stringparser", + "xakon", + "ZapAnton" + ], + "files": { + "solution": [ + "src/lib.rs", + "Cargo.toml" + ], + "test": [ + "tests/nth_prime.rs" + ], + "example": [ + ".meta/example.rs" + ] + }, + "blurb": "Given a number n, determine what the nth prime is.", + "source": "A variation on Problem 7 at Project Euler", + "source_url": "https://projecteuler.net/problem=7" +} diff --git a/rust/nth-prime/.gitignore b/rust/nth-prime/.gitignore new file mode 100644 index 0000000..96ef6c0 --- /dev/null +++ b/rust/nth-prime/.gitignore @@ -0,0 +1,2 @@ +/target +Cargo.lock diff --git a/rust/nth-prime/Cargo.toml b/rust/nth-prime/Cargo.toml new file mode 100644 index 0000000..ce719bc --- /dev/null +++ b/rust/nth-prime/Cargo.toml @@ -0,0 +1,9 @@ +[package] +name = "nth_prime" +version = "0.1.0" +edition = "2024" + +# Not all libraries from crates.io are available in Exercism's test runner. +# The full list of available libraries is here: +# https://github.com/exercism/rust-test-runner/blob/main/local-registry/Cargo.toml +[dependencies] diff --git a/rust/nth-prime/HELP.md b/rust/nth-prime/HELP.md new file mode 100644 index 0000000..22a6c00 --- /dev/null +++ b/rust/nth-prime/HELP.md @@ -0,0 +1,89 @@ +# Help + +## Running the tests + +Execute the tests with: + +```bash +$ cargo test +``` + +All but the first test have been ignored. After you get the first test to +pass, open the tests source file which is located in the `tests` directory +and remove the `#[ignore]` flag from the next test and get the tests to pass +again. Each separate test is a function with `#[test]` flag above it. +Continue, until you pass every test. + +If you wish to run _only ignored_ tests without editing the tests source file, use: + +```bash +$ cargo test -- --ignored +``` + +If you are using Rust 1.51 or later, you can run _all_ tests with + +```bash +$ cargo test -- --include-ignored +``` + +To run a specific test, for example `some_test`, you can use: + +```bash +$ cargo test some_test +``` + +If the specific test is ignored, use: + +```bash +$ cargo test some_test -- --ignored +``` + +To learn more about Rust tests refer to the online [test documentation][rust-tests]. + +[rust-tests]: https://doc.rust-lang.org/book/ch11-02-running-tests.html + +## Submitting your solution + +You can submit your solution using the `exercism submit src/lib.rs Cargo.toml` command. +This command will upload your solution to the Exercism website and print the solution page's URL. + +It's possible to submit an incomplete solution which allows you to: + +- See how others have completed the exercise +- Request help from a mentor + +## Need to get help? + +If you'd like help solving the exercise, check the following pages: + +- The [Rust track's documentation](https://exercism.org/docs/tracks/rust) +- The [Rust track's programming category on the forum](https://forum.exercism.org/c/programming/rust) +- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5) +- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs) + +Should those resources not suffice, you could submit your (incomplete) solution to request mentoring. + +## Rust Installation + +Refer to the [exercism help page][help-page] for Rust installation and learning +resources. + +## Submitting the solution + +Generally you should submit all files in which you implemented your solution (`src/lib.rs` in most cases). If you are using any external crates, please consider submitting the `Cargo.toml` file. This will make the review process faster and clearer. + +## Feedback, Issues, Pull Requests + +Head to [the forum](https://forum.exercism.org/c/programming/rust/) and create a post to provide feedback about an exercise or if you want to help implement new exercises. +Members of the rust track team are happy to help! + +The GitHub [track repository][github] is the home for all of the Rust exercises. + +If you want to know more about Exercism, take a look at the [contribution guide]. + +## Submitting Incomplete Solutions +It's possible to submit an incomplete solution so you can see how others have completed the exercise. + +[help-page]: https://exercism.org/tracks/rust/learning +[github]: https://github.com/exercism/rust +[contribution guide]: https://exercism.org/docs/community/contributors \ No newline at end of file diff --git a/rust/nth-prime/README.md b/rust/nth-prime/README.md new file mode 100644 index 0000000..6737141 --- /dev/null +++ b/rust/nth-prime/README.md @@ -0,0 +1,42 @@ +# Nth Prime + +Welcome to Nth Prime on Exercism's Rust Track. +If you need help running the tests or submitting your code, check out `HELP.md`. + +## Instructions + +Given a number n, determine what the nth prime is. + +By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13. + +If your language provides methods in the standard library to deal with prime numbers, pretend they don't exist and implement them yourself. + +Remember that while people commonly count with 1-based indexing (i.e. "the 6th prime is 13"), many programming languages, including Rust, use 0-based indexing (i.e. `primes[5] == 13`). Use 0-based indexing for your implementation. + +## Source + +### Created by + +- @sacherjj + +### Contributed to by + +- @attilahorvath +- @cbzehner +- @coriolinus +- @cwhakes +- @eddyp +- @efx +- @ErikSchierboom +- @imbolc +- @lutostag +- @nfiles +- @petertseng +- @rofrol +- @stringparser +- @xakon +- @ZapAnton + +### Based on + +A variation on Problem 7 at Project Euler - https://projecteuler.net/problem=7 \ No newline at end of file diff --git a/rust/nth-prime/src/lib.rs b/rust/nth-prime/src/lib.rs new file mode 100644 index 0000000..d44f7e0 --- /dev/null +++ b/rust/nth-prime/src/lib.rs @@ -0,0 +1,48 @@ +const PRIME_LEN: usize = 10_010; +const LIMIT: usize = 106_000; + +struct PrimeCache { + primes: [u32; PRIME_LEN], +} + +impl PrimeCache { + const fn new() -> Self { + let mut primes = [0; PRIME_LEN]; + let mut sieve = [true; LIMIT]; + + sieve[0] = false; + sieve[1] = false; + + let mut i = 2; + while i * i < LIMIT { + if sieve[i] { + let mut j = i * i; + while j < LIMIT { + sieve[j] = false; + j += i; + } + } + i += 1; + } + let mut num = 0; + let mut j = 0; + while num < LIMIT && j < PRIME_LEN { + if sieve[num] { + primes[j] = num as u32; + j += 1; + } + num += 1; + } + Self { primes } + } +} + +static CACHE: PrimeCache = PrimeCache::new(); + +pub fn nth(n: u32) -> u32 { + let nth = n as usize; + if nth >= PRIME_LEN { + panic!("N more than comptime was calculated"); + } + CACHE.primes[nth] +} diff --git a/rust/nth-prime/tests/nth_prime.rs b/rust/nth-prime/tests/nth_prime.rs new file mode 100644 index 0000000..2661377 --- /dev/null +++ b/rust/nth-prime/tests/nth_prime.rs @@ -0,0 +1,29 @@ +use nth_prime::*; + +#[test] +fn first_prime() { + let output = nth(0); + let expected = 2; + assert_eq!(output, expected); +} + +#[test] +fn second_prime() { + let output = nth(1); + let expected = 3; + assert_eq!(output, expected); +} + +#[test] +fn sixth_prime() { + let output = nth(5); + let expected = 13; + assert_eq!(output, expected); +} + +#[test] +fn big_prime() { + let output = nth(10_000); + let expected = 104_743; + assert_eq!(output, expected); +}