Complete 2023 day7 part 1

2023/day7/src/main.rs

@@ -1,4 +1,3 @@
-use crate::CardType::Four;
 use crate::HandType::{
     FiveOfAKind, FourOfAKind, FullHouse, HighCard, OnePair, ThreeOfAKind, TwoPair,
 };
@@ -6,7 +5,7 @@ use std::cmp::Ordering;
 use std::collections::HashMap;
 
 const FILE_STR: &str = include_str!("input.txt");
-const EXAMPLE_FILE_STR: &str = include_str!("example-input.txt");
+
 #[derive(Clone, Debug, Default, PartialOrd, Ord, PartialEq, Eq, Hash)]
 #[repr(u8)]
 enum CardType {
@@ -49,9 +48,10 @@ impl From<char> for CardType {
     }
 }
 
-#[derive(Debug, Default)]
+#[derive(Debug, Default, PartialEq, Eq)]
 struct Hand {
     cards: [CardType; 5],
+    kind: HandType,
     bet: usize,
 }
 
@@ -68,12 +68,37 @@ impl Hand {
             .try_into()
             .unwrap();
         let bet = raw_bet.trim().parse::<usize>().unwrap();
+        let kind = HandType::from(cards.clone());
 
-        Hand { cards, bet }
+        Hand { cards, kind, bet }
     }
 }
 
-#[derive(Debug, Default, PartialOrd, Ord, PartialEq, Eq)]
+impl PartialOrd for Hand {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for Hand {
+    /// Implement the sorting for each hand, first comparing the type of
+    /// hand, and then comparing the individual cards, if necessary
+    fn cmp(&self, other: &Self) -> Ordering {
+        if self.kind != other.kind {
+            return self.kind.cmp(&other.kind);
+        }
+
+        for (i, card) in self.cards.iter().enumerate() {
+            if card != &other.cards[i] {
+                return card.cmp(&other.cards[i]);
+            }
+        }
+
+        Ordering::Equal
+    }
+}
+
+#[derive(Debug, Default, PartialOrd, Ord, PartialEq, Eq, Copy, Clone)]
 #[repr(u8)]
 enum HandType {
     #[default]
@@ -113,13 +138,9 @@ impl From<[CardType; 5]> for HandType {
     }
 }
 
-type Rank = u16;
-type HandInd = usize;
-
 #[derive(Debug, Default)]
 struct Game {
     hands: Vec<Hand>,
-    rank: HashMap<Rank, HandInd>,
 }
 
 impl Game {
@@ -130,19 +151,41 @@ impl Game {
             .map(Hand::parse)
             .collect::<Vec<Hand>>();
 
-        Game {
-            hands,
-            ..Default::default()
+        Game { hands }
     }
+
+    fn get_score_sum(&mut self) -> usize {
+        // Rank the hands
+        self.hands.sort_unstable();
+
+        self.hands.iter().enumerate().fold(0, |prev, curr| {
+            let (i, hand) = curr;
+            let rank = i + 1;
+
+            prev + (rank * hand.bet)
+        })
     }
 }
 
+fn part_one() {
+    let mut game = Game::parse(FILE_STR);
+    let score = game.get_score_sum();
+
+    println!("Part 1: Sum of scores: {}", score);
+}
+
 fn main() {
-    let game = Game::parse(EXAMPLE_FILE_STR);
-    println!("{:#?}", game);
+    part_one();
 }
 
 #[cfg(test)]
 mod test {
+    const EXAMPLE_FILE_STR: &str = include_str!("example-input.txt");
     use super::*;
+
+    #[test]
+    fn get_score_sum() {
+        let mut game = Game::parse(EXAMPLE_FILE_STR);
+        assert_eq!(6440, game.get_score_sum());
+    }
 }