solution: day 7 clean

data/examples/07.txt

@@ -0,0 +1,5 @@
+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483

src/bin/07.rs

@@ -0,0 +1,191 @@
+use std::{cmp::Ordering, collections::HashMap, str::FromStr};
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
+enum Label {
+    Ace = 14,
+    King = 13,
+    Queen = 12,
+    Jack = 11,
+    Ten = 10,
+    Nine = 9,
+    Eight = 8,
+    Seven = 7,
+    Six = 6,
+    Five = 5,
+    Four = 4,
+    Three = 3,
+    Two = 2,
+    Joker = 1,
+}
+
+impl From<char> for Label {
+    fn from(value: char) -> Self {
+        use Label::*;
+        match value {
+            'A' => Ace,
+            'K' => King,
+            'Q' => Queen,
+            'J' => Jack,
+            'T' => Ten,
+            '9' => Nine,
+            '8' => Eight,
+            '7' => Seven,
+            '6' => Six,
+            '5' => Five,
+            '4' => Four,
+            '3' => Three,
+            '2' => Two,
+            'X' => Joker,
+            _ => unreachable!(),
+        }
+    }
+}
+
+#[derive(Debug)]
+struct ParseHandError;
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+struct Hand {
+    labels: [Label; 5],
+}
+
+impl FromStr for Hand {
+    type Err = ParseHandError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let labels = s
+            .chars()
+            .map(Label::from)
+            .collect::<Vec<_>>()
+            .try_into()
+            .map_err(|_| ParseHandError)?;
+        Ok(Hand { labels })
+    }
+}
+
+impl PartialOrd for Hand {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for Hand {
+    fn cmp(&self, other: &Self) -> Ordering {
+        let sf = HandType::from(*self);
+        let so = HandType::from(*other);
+
+        sf.cmp(&so).then({
+            let mut c = Ordering::Equal;
+            for i in 0..5 {
+                c = self.labels[i].cmp(&other.labels[i]);
+                if c != Ordering::Equal {
+                    break;
+                }
+            }
+            c
+        })
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+enum HandType {
+    Five = 6,
+    Four = 5,
+    FullHouse = 4,
+    Three = 3,
+    TwoPair = 2,
+    Pair = 1,
+    HighCard = 0,
+}
+
+impl From<Hand> for HandType {
+    fn from(value: Hand) -> Self {
+        let mut map = HashMap::new();
+
+        for c in value.labels {
+            *map.entry(c).or_insert(0) += 1;
+        }
+
+        let joker = map.remove(&Label::Joker).unwrap_or(0);
+
+        let is_n_k = |n| joker == n || map.values().filter(|&x| *x == n - joker).count() > 0;
+
+        if is_n_k(5) {
+            return Self::Five;
+        }
+        if is_n_k(4) {
+            return Self::Four;
+        }
+        // full house
+        if map.values().count() <= 2 {
+            return Self::FullHouse;
+        }
+        if is_n_k(3) {
+            return Self::Three;
+        }
+        // two pair
+        if map.values().count() <= 3 {
+            return Self::TwoPair;
+        }
+        if is_n_k(2) {
+            return Self::Pair;
+        }
+
+        Self::HighCard
+    }
+}
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let mut v = input
+        .lines()
+        .filter_map(|l| l.split_once(' '))
+        .map(|(f, s)| (f.parse::<Hand>().unwrap(), s.parse::<u32>().unwrap()))
+        .collect::<Vec<_>>();
+
+    v.sort_by(|f, o| f.0.cmp(&o.0));
+
+    Some(
+        v.into_iter()
+            .enumerate()
+            .map(|(i, x)| (i as u32 + 1) * x.1)
+            .sum::<u32>(),
+    )
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let mut v = input
+        .replace('J', "X")
+        .lines()
+        .filter_map(|l| l.split_once(' '))
+        .map(|(f, s)| (f.parse::<Hand>().unwrap(), s.parse::<u32>().unwrap()))
+        .collect::<Vec<_>>();
+
+    v.sort_by(|f, o| f.0.cmp(&o.0));
+
+    Some(
+        v.into_iter()
+            .enumerate()
+            .map(|(i, x)| (i as u32 + 1) * x.1)
+            .sum::<u32>(),
+    )
+}
+
+aoc::solution!(7);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_part_one() {
+        assert_eq!(
+            part_one(&aoc::template::read_file("examples", 7)),
+            Some(6440)
+        );
+    }
+    #[test]
+    fn test_part_two() {
+        assert_eq!(
+            part_two(&aoc::template::read_file("examples", 7)),
+            Some(5905)
+        );
+    }
+}