-
Notifications
You must be signed in to change notification settings - Fork 2
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
4 changed files
with
298 additions
and
2 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,284 @@ | ||
| use std::collections::BTreeMap; | ||
| use std::ops::{Add, Div, Mul, Neg, Rem, Sub}; | ||
| use std::str::FromStr; | ||
|
|
||
| enum Operation { | ||
| Add, | ||
| Sub, | ||
| Mul, | ||
| Div, | ||
| } | ||
| impl FromStr for Operation { | ||
| type Err = (); | ||
| fn from_str(s: &str) -> Result<Self, Self::Err> { | ||
| match s { | ||
| "+" => Ok(Self::Add), | ||
| "-" => Ok(Self::Sub), | ||
| "*" => Ok(Self::Mul), | ||
| "/" => Ok(Self::Div), | ||
| _ => Err(()), | ||
| } | ||
| } | ||
| } | ||
|
|
||
| enum Expr<T, R> { | ||
| Literal(T), | ||
| Binary(R, Operation, R), | ||
| } | ||
|
|
||
| fn parse<'a, I, S>(lines: I) -> Option<BTreeMap<&'a str, Expr<isize, &'a str>>> | ||
| where | ||
| I: IntoIterator<Item = &'a S>, | ||
| S: AsRef<str> + 'a, | ||
| { | ||
| lines | ||
| .into_iter() | ||
| .map(|line| { | ||
| let (name, definition) = line.as_ref().split_once(": ")?; | ||
| match definition.parse() { | ||
| Ok(value) => Some((name, Expr::Literal(value))), | ||
| _ => { | ||
| let mut iter = definition.split(' '); | ||
| Some(( | ||
| name, | ||
| Expr::Binary(iter.next()?, iter.next()?.parse().ok()?, iter.next()?), | ||
| )) | ||
| .filter(|_| iter.next().is_none()) | ||
| } | ||
| } | ||
| }) | ||
| .collect() | ||
| } | ||
|
|
||
| pub fn part1<'a, I, S>(lines: I) -> Option<isize> | ||
| where | ||
| I: IntoIterator<Item = &'a S>, | ||
| S: AsRef<str> + 'a, | ||
| { | ||
| let definitions = parse(lines)?; | ||
| fn eval(definitions: &BTreeMap<&str, Expr<isize, &str>>, name: &str) -> Option<isize> { | ||
| match definitions.get(name)? { | ||
| Expr::Literal(value) => Some(*value), | ||
| Expr::Binary(lhs, op, rhs) => { | ||
| let lhs = eval(definitions, lhs)?; | ||
| let rhs = eval(definitions, rhs)?; | ||
| match op { | ||
| Operation::Add => lhs.checked_add(rhs), | ||
| Operation::Sub => lhs.checked_sub(rhs), | ||
| Operation::Mul => lhs.checked_mul(rhs), | ||
| Operation::Div => lhs.checked_div(rhs), | ||
| } | ||
| } | ||
| } | ||
| } | ||
| eval(&definitions, "root") | ||
| } | ||
|
|
||
| #[derive(Clone, Copy, Eq, PartialEq)] | ||
| struct Ratio<T> { | ||
| numerator: T, | ||
| denominator: T, | ||
| } | ||
| impl<T> Add<Ratio<T>> for Ratio<T> | ||
| where | ||
| T: Add<T, Output = T> | ||
| + Copy | ||
| + Div<T, Output = T> | ||
| + From<bool> | ||
| + Mul<T, Output = T> | ||
| + Neg<Output = T> | ||
| + Ord | ||
| + Rem<T, Output = T>, | ||
| { | ||
| type Output = Self; | ||
| fn add(self, rhs: Ratio<T>) -> Self::Output { | ||
| let gcd1 = gcd(self.denominator, rhs.denominator); | ||
| let multiplier = self.denominator / gcd1; | ||
| let numerator = self.numerator * (rhs.denominator / gcd1) + rhs.numerator * multiplier; | ||
| let denominator = multiplier * rhs.denominator; | ||
| let gcd2 = gcd(numerator, denominator); | ||
| Ratio { | ||
| numerator: numerator / gcd2, | ||
| denominator: denominator / gcd2, | ||
| } | ||
| } | ||
| } | ||
| impl<T> Sub<Ratio<T>> for Ratio<T> | ||
| where | ||
| T: Copy | ||
| + Div<T, Output = T> | ||
| + From<bool> | ||
| + Mul<T, Output = T> | ||
| + Neg<Output = T> | ||
| + Ord | ||
| + Rem<T, Output = T> | ||
| + Sub<T, Output = T>, | ||
| { | ||
| type Output = Self; | ||
| fn sub(self, rhs: Ratio<T>) -> Self::Output { | ||
| let gcd1 = gcd(self.denominator, rhs.denominator); | ||
| let multiplier = self.denominator / gcd1; | ||
| let numerator = self.numerator * (rhs.denominator / gcd1) - rhs.numerator * multiplier; | ||
| let denominator = multiplier * rhs.denominator; | ||
| let gcd2 = gcd(numerator, denominator); | ||
| Ratio { | ||
| numerator: numerator / gcd2, | ||
| denominator: denominator / gcd2, | ||
| } | ||
| } | ||
| } | ||
| impl<T> Mul<Ratio<T>> for Ratio<T> | ||
| where | ||
| T: Copy | ||
| + Div<T, Output = T> | ||
| + From<bool> | ||
| + Mul<T, Output = T> | ||
| + Neg<Output = T> | ||
| + Ord | ||
| + Rem<T, Output = T>, | ||
| { | ||
| type Output = Self; | ||
| fn mul(self, rhs: Ratio<T>) -> Self::Output { | ||
| let gcd1 = gcd(self.numerator, rhs.denominator); | ||
| let gcd2 = gcd(rhs.numerator, self.denominator); | ||
| Ratio { | ||
| numerator: (self.numerator / gcd1) * (rhs.numerator / gcd2), | ||
| denominator: (self.denominator / gcd2) * (rhs.denominator / gcd1), | ||
| } | ||
| } | ||
| } | ||
| impl<T> Div<Ratio<T>> for Ratio<T> | ||
| where | ||
| T: Copy | ||
| + Div<T, Output = T> | ||
| + From<bool> | ||
| + Mul<T, Output = T> | ||
| + Neg<Output = T> | ||
| + Ord | ||
| + Rem<T, Output = T>, | ||
| { | ||
| type Output = Self; | ||
| fn div(self, rhs: Ratio<T>) -> Self::Output { | ||
| assert!(rhs.numerator != false.into()); | ||
| let gcd1 = gcd(self.numerator, rhs.numerator); | ||
| let gcd2 = gcd(rhs.denominator, self.denominator); | ||
| Ratio { | ||
| numerator: (self.numerator / gcd1) * (rhs.denominator / gcd2), | ||
| denominator: (self.denominator / gcd2) * (rhs.numerator / gcd1), | ||
| } | ||
| } | ||
| } | ||
| impl<T: From<bool>> From<T> for Ratio<T> { | ||
| fn from(value: T) -> Self { | ||
| Ratio { | ||
| numerator: value, | ||
| denominator: true.into(), | ||
| } | ||
| } | ||
| } | ||
| impl TryFrom<Ratio<isize>> for isize { | ||
| type Error = (); | ||
| fn try_from(value: Ratio<isize>) -> Result<Self, Self::Error> { | ||
| if value.denominator == 1 { | ||
| Ok(value.numerator) | ||
| } else { | ||
| Err(()) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| fn gcd<T: Copy + From<bool> + Neg<Output = T> + Ord + Rem<T, Output = T>>(a: T, b: T) -> T { | ||
| let mut x = a; | ||
| let mut y = b; | ||
| while y != false.into() { | ||
| let tmp = x; | ||
| x = y; | ||
| y = tmp % y; | ||
| } | ||
| if (x < false.into()) != (b < false.into()) { | ||
| -x | ||
| } else { | ||
| x | ||
| } | ||
| } | ||
|
|
||
| pub fn part2<'a, I, S>(lines: I) -> Option<isize> | ||
| where | ||
| I: IntoIterator<Item = &'a S>, | ||
| S: AsRef<str> + 'a, | ||
| { | ||
| let definitions = parse(lines)?; | ||
| fn eval( | ||
| definitions: &BTreeMap<&str, Expr<isize, &str>>, | ||
| name: &str, | ||
| ) -> Option<(Ratio<isize>, Ratio<isize>)> { | ||
| if name == "humn" { | ||
| return Some((1.into(), 0.into())); | ||
| } | ||
| match definitions.get(name)? { | ||
| Expr::Literal(value) => Some((0.into(), (*value).into())), | ||
| Expr::Binary(lhs, op, rhs) => { | ||
| let lhs = eval(definitions, lhs)?; | ||
| let rhs = eval(definitions, rhs)?; | ||
| match op { | ||
| Operation::Add => Some((lhs.0 + rhs.0, lhs.1 + rhs.1)), | ||
| Operation::Sub => Some((lhs.0 - rhs.0, lhs.1 - rhs.1)), | ||
| Operation::Mul => { | ||
| if lhs.0 == 0.into() { | ||
| Some((lhs.1 * rhs.0, lhs.1 * rhs.1)) | ||
| } else if rhs.0 == 0.into() { | ||
| Some((lhs.0 * rhs.1, lhs.1 * rhs.1)) | ||
| } else { | ||
| None | ||
| } | ||
| } | ||
| Operation::Div => { | ||
| if rhs.0 == 0.into() { | ||
| Some((lhs.0 / rhs.1, lhs.1 / rhs.1)) | ||
| } else { | ||
| None | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
| let &Expr::Binary(lhs, _, rhs) = definitions.get("root")? else { return None }; | ||
| let lhs = eval(&definitions, lhs)?; | ||
| let rhs = eval(&definitions, rhs)?; | ||
| ((lhs.1 - rhs.1) / (rhs.0 - lhs.0)).try_into().ok() | ||
| } | ||
|
|
||
| #[cfg(test)] | ||
| mod tests { | ||
| use super::*; | ||
| use pretty_assertions::assert_eq; | ||
|
|
||
| static EXAMPLE: &[&str] = &[ | ||
| "root: pppw + sjmn", | ||
| "dbpl: 5", | ||
| "cczh: sllz + lgvd", | ||
| "zczc: 2", | ||
| "ptdq: humn - dvpt", | ||
| "dvpt: 3", | ||
| "lfqf: 4", | ||
| "humn: 5", | ||
| "ljgn: 2", | ||
| "sjmn: drzm * dbpl", | ||
| "sllz: 4", | ||
| "pppw: cczh / lfqf", | ||
| "lgvd: ljgn * ptdq", | ||
| "drzm: hmdt - zczc", | ||
| "hmdt: 32", | ||
| ]; | ||
|
|
||
| #[test] | ||
| fn part1_examples() { | ||
| assert_eq!(Some(152), part1(EXAMPLE)); | ||
| } | ||
|
|
||
| #[test] | ||
| fn part2_examples() { | ||
| assert_eq!(Some(301), part2(EXAMPLE)); | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters