Solved part 1 of day 7

Fix: numbers for strength in second ordering was an exclusive range
instead of an inclusive range

Tidied up code for readability

src/main.rs

@@ -7,6 +7,7 @@ use thiserror::Error;
 
 fn main() -> ExitCode {
     let args = AppCliArguments::parse();
+    env_logger::init();
     let solution = solve_given(&args);
     match solution {
         Ok(found_solution) => {

src/solutions/day7.rs

@@ -4,8 +4,8 @@ mod categorized_hand;
 mod dealt_hand;
 mod hand_kind;
 mod parsing;
+mod second_ordering;
 
-/// TODO: wrong answer for 253639210 is too low for my puzzle input
 pub fn solve_task_1(input: &str) -> String {
     let parsed = parsing::parse_input(input);
     let sorted_and_categorized = {
@@ -13,17 +13,23 @@ pub fn solve_task_1(input: &str) -> String {
         categorized.sort();
         categorized
     };
-    let total_score = calc_bid_and_ranks(&sorted_and_categorized);
-    total_score.to_string()
+    let total_winning = calc_total_winning(&sorted_and_categorized);
+    total_winning.to_string()
 }
 
-fn calc_bid_and_ranks(sorted: &[CategorizedHand]) -> usize {
+fn calc_total_winning(sorted: &[CategorizedHand]) -> usize {
     sorted
         .into_iter()
         .enumerate()
         .map(|(index, hand)| {
-            let rank = index + 1;
-            hand.score() * rank
+            let rank = index.saturating_add(1);
+            let score = hand.bid();
+            score.checked_mul(rank).unwrap_or_else(|| {
+                panic!(
+                    "Multiplication of score ({}) with rank ({}) resulted in overflow",
+                    score, rank
+                )
+            })
         })
         .sum()
 }

src/solutions/day7/categorized_hand.rs

@@ -1,9 +1,8 @@
-use std::{
-    cmp::{Ordering, Reverse},
-    collections::HashMap,
-    sync::LazyLock,
-    usize,
-};
+use std::{cmp::Reverse, collections::HashMap, usize};
+
+use log::warn;
+
+use crate::solutions::day7::second_ordering;
 
 use super::{dealt_hand::DealtHand, hand_kind::HandKind};
 
@@ -17,16 +16,34 @@ impl CategorizedHand {
     pub fn rest(&self) -> &DealtHand {
         &self.rest
     }
-    pub fn score(&self) -> usize {
-        self.rest().score()
+    pub fn bid(&self) -> usize {
+        self.rest().bid()
     }
 }
 
 impl Ord for CategorizedHand {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
         match self.kind.cmp(&other.kind) {
-            std::cmp::Ordering::Equal => compare_along_str(self.rest().hand(), other.rest().hand()),
-            not_equal_ordering => not_equal_ordering,
+            std::cmp::Ordering::Equal => {
+                assert!(
+                    self.kind == other.kind,
+                    "If ordering is equal then the hand kind must be the same too\n\
+                    Self kind: ({:?}) and other kind: ({:?})",
+                    self.kind,
+                    other.kind
+                );
+                second_ordering::compare_along_str(self.rest().hand(), other.rest().hand())
+            }
+            not_equal_ordering => {
+                assert!(
+                    self.kind != other.kind,
+                    "If ordering is not equal then the hand kind must not be the same either\n\
+                    Self kind: ({:?}) and other kind: ({:?})",
+                    self.kind,
+                    other.kind
+                );
+                not_equal_ordering
+            }
         }
     }
 }
@@ -37,63 +54,60 @@ impl PartialOrd for CategorizedHand {
     }
 }
 
-static LABEL_ORDERING: LazyLock<HashMap<char, usize>> = LazyLock::new(|| {
-    let numbers = (0..9)
-        .into_iter()
-        .map(|number| std::char::from_digit(number, 10).unwrap());
-    let letters = ['T', 'J', 'Q', 'K', 'A'];
-    numbers
-        .chain(letters.into_iter())
-        .into_iter()
-        .enumerate()
-        .map(|(index, character)| (character, index))
-        .collect()
-});
-//A hand consists of five cards labeled one of A, K, Q, J, T, 9, 8, 7, 6, 5, 4, 3, or 2.
-//The relative strength of each card follows this order, where A is the highest and 2 is the lowest.
-fn compare_along_str(left: &str, right: &str) -> Ordering {
-    for (left_char, right_char) in left.chars().zip(right.chars()) {
-        let left_rank_value = LABEL_ORDERING.get(&left_char);
-        let right_rank_value = LABEL_ORDERING.get(&right_char);
-        let current_ordering = left_rank_value.cmp(&right_rank_value);
-        if current_ordering != Ordering::Equal {
-            return current_ordering;
-        }
-    }
-    left.len().cmp(&right.len())
-}
-
 impl From<DealtHand> for CategorizedHand {
     fn from(value: DealtHand) -> Self {
-        let mut count_of_same: HashMap<char, usize> = HashMap::with_capacity(10);
-        for next_char in value.hand().chars() {
-            count_of_same
-                .entry(next_char)
-                .and_modify(|count| *count = *count + 1)
-                .or_insert(1);
-        }
-        let values = {
-            let mut to_sort: Vec<usize> =
-                count_of_same.into_iter().map(|(_, count)| count).collect();
-            to_sort.sort_by_key(|&count| Reverse(count));
-            to_sort
-        };
+        fn calc_kind(values: &[usize]) -> Option<HandKind> {
+            let max = values.first()?;
 
-        let max = values.first().unwrap();
-        let kind = match max {
-            5 => HandKind::Five,
-            4 => HandKind::Four,
-            _ => {
-                let second = values.get(1).unwrap();
-                match (max, second) {
-                    (3, 2) => HandKind::FullHouse,
-                    (3, _) => HandKind::Three,
-                    (2, 2) => HandKind::TwoPair,
-                    (2, 1) => HandKind::OnePair,
-                    _ => HandKind::HighCard,
+            let kind = match max {
+                5 => HandKind::Five,
+                4 => HandKind::Four,
+                under_five_or_four => {
+                    let second_after_max = values.get(1)?;
+                    match (under_five_or_four, second_after_max) {
+                        (3, 2) => HandKind::FullHouse,
+                        (3, _) => HandKind::Three,
+                        (2, 2) => HandKind::TwoPair,
+                        (2, 1) => HandKind::OnePair,
+                        _no_duplicates => HandKind::HighCard,
+                    }
                 }
+            };
+
+            Some(kind)
+        }
+
+        fn calc_duplicate_counted(value: &DealtHand) -> Vec<usize> {
+            const FIRST_ENCOUNTERED: usize = 1;
+
+            let mut count_of_same: HashMap<char, usize> = HashMap::with_capacity(10);
+
+            for next_char in value.hand().chars() {
+                count_of_same
+                    .entry(next_char)
+                    .and_modify(|count| *count = *count + 1)
+                    .or_insert(FIRST_ENCOUNTERED);
             }
-        };
+
+            {
+                let mut to_sort: Vec<usize> =
+                    count_of_same.into_iter().map(|(_, count)| count).collect();
+                to_sort.sort_by_key(|&count| Reverse(count));
+                to_sort
+            }
+        }
+
+        let duplicated_counted = calc_duplicate_counted(&value);
+
+        let kind = calc_kind(&duplicated_counted).unwrap_or_else(|| {
+            warn!(
+                "Got hand ({:?}) with less than 2 cards",
+                &duplicated_counted
+            );
+            let default_value = HandKind::default();
+            warn!("Default kind ({:?}) is assumed", default_value);
+            default_value
+        });
 
         CategorizedHand { kind, rest: value }
     }
@@ -128,7 +142,7 @@ mod testing {
     }
 
     #[test]
-    fn correct_cmp() {
+    fn compare_correctly_by_kind_and_second_ordering() {
         fn assert_case(left: DealtHand, right: DealtHand, expected: Ordering) {
             let (left, right): (CategorizedHand, CategorizedHand) = (left.into(), right.into());
             let actual = left.cmp(&right);
@@ -163,6 +177,28 @@ mod testing {
             DealtHand::new("KTJJT", 30),
             Ordering::Greater,
         );
+
+        //So, 33332 and 2AAAA are both four of a kind hands,
+        //but 33332 is stronger because its first card is stronger.
+        assert_case(
+            DealtHand::new("33332", 20),
+            DealtHand::new("2AAAA", 30),
+            Ordering::Greater,
+        );
+
+        //Similarly, 77888 and 77788 are both a full house,
+        //but 77888 is stronger because its third card is stronger
+        //(and both hands have the same first and second card).
+        assert_case(
+            DealtHand::new("77788", 30),
+            DealtHand::new("77888", 20),
+            Ordering::Less,
+        );
+        assert_case(
+            DealtHand::new("19231", 30),
+            DealtHand::new("18231", 20),
+            Ordering::Greater,
+        );
     }
 
     #[test]

src/solutions/day7/dealt_hand.rs

@@ -6,22 +6,22 @@ use thiserror::Error;
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub struct DealtHand {
     hand: String,
-    score: usize,
+    bid: usize,
 }
 
 impl DealtHand {
     #[cfg(test)]
     pub fn new(hand: impl Into<String>, score: usize) -> Self {
         let hand = hand.into();
-        Self { hand, score }
+        Self { hand, bid: score }
     }
 
     pub fn hand(&self) -> &str {
         &self.hand
     }
 
-    pub fn score(&self) -> usize {
-        self.score
+    pub const fn bid(&self) -> usize {
+        self.bid
     }
 }
 
@@ -44,7 +44,7 @@ impl FromStr for DealtHand {
                     .parse()
                     .map_err(|_| InvalidStrDealtHand::InvalidUnsignedNumberScore)?;
                 let hand = hand.to_string();
-                let done = DealtHand { hand, score };
+                let done = DealtHand { hand, bid: score };
                 Ok(done)
             }
             _ => Err(InvalidStrDealtHand::Not2Elements),
@@ -68,35 +68,35 @@ mod testing {
                 "32T3K 765",
                 Ok(DealtHand {
                     hand: "32T3K".to_string(),
-                    score: 765,
+                    bid: 765,
                 }),
             );
             assert_case(
                 "T55J5 684",
                 Ok(DealtHand {
                     hand: "T55J5".to_string(),
-                    score: 684,
+                    bid: 684,
                 }),
             );
             assert_case(
                 "KK677 28",
                 Ok(DealtHand {
                     hand: "KK677".to_string(),
-                    score: 28,
+                    bid: 28,
                 }),
             );
             assert_case(
                 "KTJJT 220",
                 Ok(DealtHand {
                     hand: "KTJJT".to_string(),
-                    score: 220,
+                    bid: 220,
                 }),
             );
             assert_case(
                 "QQQJA 483",
                 Ok(DealtHand {
                     hand: "QQQJA".to_string(),
-                    score: 483,
+                    bid: 483,
                 }),
             );
         }

src/solutions/day7/hand_kind.rs

@@ -1,6 +1,7 @@
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default)]
 pub enum HandKind {
     /// High card, where all cards' labels are distinct: 23456
+    #[default]
     HighCard,
     /// One pair, where two cards share one label, and the other three cards have a different label from the pair and each other: A23A4
     OnePair,

src/solutions/day7/second_ordering.rs

@@ -0,0 +1,45 @@
+use std::{cmp::Ordering, collections::HashMap, ops::RangeInclusive, sync::LazyLock, usize};
+
+use log::warn;
+
+static LETTERS: &[char] = &['T', 'J', 'Q', 'K', 'A'];
+const NUMBERS: RangeInclusive<u32> = 0..=9;
+
+static LABEL_ORDERING: LazyLock<HashMap<char, usize>> = LazyLock::new(|| {
+    let numbers = NUMBERS
+        .into_iter()
+        .map(|number| std::char::from_digit(number, 10).unwrap());
+    numbers
+        .chain(LETTERS.into_iter().copied())
+        .into_iter()
+        .enumerate()
+        .map(|(index, character)| (character, index))
+        .collect()
+});
+//
+//A hand consists of five cards labeled one of A, K, Q, J, T, 9, 8, 7, 6, 5, 4, 3, or 2.
+//The relative strength of each card follows this order, where A is the highest and 2 is the lowest.
+pub fn compare_along_str(left: &str, right: &str) -> Ordering {
+    for (left_char, right_char) in left.chars().zip(right.chars()) {
+        let left_rank_value = LABEL_ORDERING
+            .get(&left_char)
+            .unwrap_or_else(|| panic!("left char ({}) is not valid", left_char));
+        let right_rank_value = LABEL_ORDERING
+            .get(&right_char)
+            .unwrap_or_else(|| panic!("right char ({}) is not valid", right_char));
+
+        let current_ordering = left_rank_value.cmp(&right_rank_value);
+
+        let found_difference = current_ordering != Ordering::Equal;
+        if found_difference {
+            return current_ordering;
+        }
+    }
+    let (left_len, right_len) = (left.len(), right.len());
+    warn!(
+        "Left and right seem to have no difference in strength\n\
+        Now comparing via lenght ({}) ({}). By same length, lefte wins !",
+        left_len, right_len
+    );
+    left_len.cmp(&right_len)
+}

src/solutions/day7/snapshots/advent_of_code_2023__solutions__day7__categorized_hand__testing__sort_example_correctly.snap

@@ -7,35 +7,35 @@ expression: input
         kind: OnePair,
         rest: DealtHand {
             hand: "32T3K",
-            score: 765,
+            bid: 765,
         },
     },
     CategorizedHand {
         kind: TwoPair,
         rest: DealtHand {
             hand: "KTJJT",
-            score: 220,
+            bid: 220,
         },
     },
     CategorizedHand {
         kind: TwoPair,
         rest: DealtHand {
             hand: "KK677",
-            score: 28,
+            bid: 28,
         },
     },
     CategorizedHand {
         kind: Three,
         rest: DealtHand {
             hand: "T55J5",
-            score: 684,
+            bid: 684,
         },
     },
     CategorizedHand {
         kind: Three,
         rest: DealtHand {
             hand: "QQQJA",
-            score: 483,
+            bid: 483,
         },
     },
 ]