Rework Levenshtein distance

[aesteve]

Rework Levenshtein distance

Description

Rework a bit the Levenshtein distance implementation by using a more Rust-idiomatic way (iterators).
Add a detailed documentation on how the algorithm works.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I ran bellow commands using the latest version of rust nightly.
• I ran cargo clippy --all -- -D warnings just before my last commit and fixed any issue that was found.
• I ran cargo fmt just before my last commit.
• I ran cargo test just before my last commit and all tests passed.
• I checked COUNTRIBUTING.md and my code follows its guidelines.

Please make sure that if there is a test that takes too long to run ( > 300ms), you #[ignore] that or
try to optimize your code or make the test easier to run. We have this rule because we have hundreds of
tests to run; If each one of them took 300ms, we would have to wait for a long time.

[aesteve]

Also, I think there's a duplicate between:

• https://github.com/TheAlgorithms/Rust/blob/master/src/dynamic_programming/edit_distance.rs
• https://github.com/TheAlgorithms/Rust/blob/master/src/string/levenshtein_distance.rs

Not sure which one should take precedence but both are implementing Levenshtein distance.

[siriak]

Please merge edit distance file into this one and delete the original. As for your changes, could you remove comments with example from the code? Examples don't need to be included if this can be looked up on Wikiipedia

[aesteve]

Thanks for the feedback.

• I fixed the 3 reviewed items, thanks for that

---

As for the rest:

• I merged edit distance into the Levenshtein distance, but kept the entry in the DIRECTORY.md under Dynamic Programming to point at the Levenshtein distance:
  • in case some people are used to look for "edit distance" in the directory maybe? so that the change is a bit backwards compatible in a sense
  • and well, because Levenshtein distance is actually dynamic programming, indeed but works on Strings. So... It kinda makes sense.

I can remove it if you want, let me know.

---

For the comments I removed them but I truly think this is a shame. Surely it can be looked be on Wikipedia, but they walked through the algorithm in a shorter yet understandable way.

[siriak]

Thanks, looks good!

It's supposed to be as close to a real-life implementation as possible so that people can not only get familiar with the algorithm, but also with the language and coding conventions. So, it's different from a book and not supposed to be a complete self-explanatory text read as a book. We don't include details that are verbose and can be googled.

It's like when using patterns, saying that we use "visitor" pattern here is enough and an explanation of what that is can be easily googled. Hope that makes sense.

[aesteve]

Makes total sense.

I probably need to rewrite the count-min-sketch ( #485 one) and a few others I was preparing (bloom filters, hyperloglog) as well then.