Skip to content

poker: remove incorrect hints about total order #2177

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
senekor wants to merge 1 commit into
base: main
Choose a base branch
from
Open

poker: remove incorrect hints about total order #2177

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 1 addition & 4 deletions exercises/practice/poker/.docs/hints.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,4 @@

- Ranking a list of poker hands can be considered a sorting problem.
- Rust provides the [sort](https://doc.rust-lang.org/std/vec/struct.Vec.html#method.sort) method for `Vec<T> where T: Ord`.
- [`Ord` types](https://doc.rust-lang.org/std/cmp/trait.Ord.html) form a [total order](https://en.wikipedia.org/wiki/Total_order): exactly one of `a < b`, `a == b`, or `a > b` must be true.
- Poker hands do not conform to a total order: it is possible for two hands to be non-equal but have equal sort order. Example: `"3S 4S 5D 6H JH"`, `"3H 4H 5C 6C JD"`.
- Rust provides the [`PartialOrd` trait](https://doc.rust-lang.org/std/cmp/trait.PartialOrd.html) to handle the case of sortable things which do not have a total order. However, it doesn't provide a standard `sort` method for `Vec<T> where T: PartialOrd`. The standard idiom to sort a vector in this case is `your_vec.sort_by(|a, b| a.partial_cmp(b).unwrap_or(Ordering::{Less|Equal|Greater}));`, depending on your needs.
- You might consider implementing a type representing a poker hand which implements `PartialOrd`.
- You might consider implementing a type representing a poker hand which implements [`Ord`](https://doc.rust-lang.org/std/cmp/trait.Ord.html).
Loading