Solved part 2 of day 7 partially

Example works
but not the real puzzle input

file_input/day7_example.txt

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

src/solutions.rs

@@ -10,7 +10,7 @@ pub fn create_solutions() -> Vec<Vec<fn(&str) -> String>> {
         vec![not_implemented_yet, not_implemented_yet],
         vec![day5::solve_task_1, day5::solve_task_2],
         vec![day6::solve_task_1, day6::solve_task_2],
-        vec![day7::solve_task_1, not_implemented_yet],
+        vec![day7::solve_task_1, day7::solve_task_2],
         vec![not_implemented_yet, not_implemented_yet],
         vec![not_implemented_yet, not_implemented_yet],
         vec![not_implemented_yet, not_implemented_yet],

src/solutions/day7.rs

@@ -1,4 +1,4 @@
-use categorized_hand::CategorizedHand;
+use categorized_hand::{CategorizedHand, JokerOrdered};
 
 mod categorized_hand;
 mod dealt_hand;
@@ -17,6 +17,26 @@ pub fn solve_task_1(input: &str) -> String {
     total_winning.to_string()
 }
 
+pub fn solve_task_2(input: &str) -> String {
+    const JOKER: char = 'J';
+    let parsed = parsing::parse_input(input);
+    let sorted_and_categorized: Vec<CategorizedHand> = {
+        let mut categorized: Vec<JokerOrdered> = parsed
+            .into_iter()
+            .map(|not_categorized| (not_categorized, JOKER).into())
+            .map(JokerOrdered::new)
+            .collect();
+        categorized.sort();
+
+        categorized
+            .into_iter()
+            .map(|to_unwrap| to_unwrap.into())
+            .collect()
+    };
+    let total_winning = calc_total_winning(&sorted_and_categorized);
+    total_winning.to_string()
+}
+
 fn calc_total_winning(sorted: &[CategorizedHand]) -> usize {
     sorted
         .into_iter()
@@ -52,4 +72,11 @@ mod testing {
         let expected = "6440";
         assert_eq!(expected, actual);
     }
+
+    #[test]
+    fn solve_example_according_to_task_2() {
+        let actual = super::solve_task_2(TEST_INPUT);
+        let expected = "5905";
+        assert_eq!(expected, actual);
+    }
 }

src/solutions/day7/categorized_hand.rs

@@ -1,10 +1,9 @@
-use std::{cmp::Reverse, collections::HashMap, usize};
-
-use log::warn;
+use derive_more::derive::Into;
 
 use crate::solutions::day7::second_ordering;
+use std::usize;
 
-use super::{dealt_hand::DealtHand, hand_kind::HandKind};
+use super::{dealt_hand::DealtHand, hand_kind::HandKind, second_ordering::StrengthOfSymbols};
 
 #[derive(Debug, PartialEq, Eq)]
 pub struct CategorizedHand {
@@ -12,7 +11,36 @@ pub struct CategorizedHand {
     rest: DealtHand,
 }
 
+#[derive(Debug, PartialEq, Eq, Into)]
+pub struct JokerOrdered(pub CategorizedHand);
+
+impl JokerOrdered {
+    pub fn new(value: CategorizedHand) -> Self {
+        Self(value)
+    }
+}
+
+impl Ord for JokerOrdered {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        hand_cmp(
+            &self.0,
+            &other.0,
+            &second_ordering::LABEL_ORDERING_WITH_JOKER,
+        )
+    }
+}
+impl PartialOrd for JokerOrdered {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
 impl CategorizedHand {
+    #[cfg(test)]
+    pub fn new(kind: HandKind, rest: DealtHand) -> Self {
+        Self { kind, rest }
+    }
+
     pub fn rest(&self) -> &DealtHand {
         &self.rest
     }
@@ -23,30 +51,42 @@ impl CategorizedHand {
 
 impl Ord for CategorizedHand {
     fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        match self.kind.cmp(&other.kind) {
+        hand_cmp(self, other, &second_ordering::LABEL_ORDERING)
+    }
+}
+
+fn hand_cmp(
+    left: &CategorizedHand,
+    right: &CategorizedHand,
+    label_ordering: &StrengthOfSymbols,
+) -> std::cmp::Ordering {
+    match left.kind.cmp(&right.kind) {
         std::cmp::Ordering::Equal => {
             assert!(
-                    self.kind == other.kind,
+                left.kind == right.kind,
                 "If ordering is equal then the hand kind must be the same too\n\
-                    Self kind: ({:?}) and other kind: ({:?})",
-                    self.kind,
-                    other.kind
+                    left kind: ({:?}) and right kind: ({:?})",
+                left.kind,
+                right.kind
             );
-                second_ordering::compare_along_str(self.rest().hand(), other.rest().hand())
+            second_ordering::compare_along_str(
+                left.rest().hand(),
+                right.rest().hand(),
+                label_ordering,
+            )
         }
         not_equal_ordering => {
             assert!(
-                    self.kind != other.kind,
+                left.kind != right.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
+                    left kind: ({:?}) and right kind: ({:?})",
+                left.kind,
+                right.kind
             );
             not_equal_ordering
         }
     }
 }
-}
 
 impl PartialOrd for CategorizedHand {
     fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
@@ -56,59 +96,13 @@ impl PartialOrd for CategorizedHand {
 
 impl From<DealtHand> for CategorizedHand {
     fn from(value: DealtHand) -> Self {
-        fn calc_kind(values: &[usize]) -> Option<HandKind> {
-            let max = values.first()?;
-
-            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,
+        let kind = value.hand().into();
+        CategorizedHand { kind, rest: value }
     }
 }
-            };
-
-            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
-        });
-
+impl From<(DealtHand, char)> for CategorizedHand {
+    fn from((value, joker): (DealtHand, char)) -> Self {
+        let kind = (value.hand(), joker).into();
         CategorizedHand { kind, rest: value }
     }
 }
@@ -117,29 +111,7 @@ impl From<DealtHand> for CategorizedHand {
 mod testing {
     use std::cmp::Ordering;
 
-    use crate::solutions::day7::{
-        categorized_hand::CategorizedHand, dealt_hand::DealtHand, hand_kind::HandKind,
-    };
-
-    #[test]
-    fn from_dealt_hand_to_categorized_hand() {
-        fn assert_case(given: DealtHand, expected: HandKind) {
-            let expected_hand = CategorizedHand {
-                kind: expected,
-                rest: given.clone(),
-            };
-            let actual = given.into();
-            assert_eq!(expected_hand, actual);
-        }
-
-        assert_case(DealtHand::new("AAAAA", 20), HandKind::Five);
-        assert_case(DealtHand::new("AA8AA", 20), HandKind::Four);
-        assert_case(DealtHand::new("23332", 20), HandKind::FullHouse);
-        assert_case(DealtHand::new("TTT98", 20), HandKind::Three);
-        assert_case(DealtHand::new("23456", 20), HandKind::HighCard);
-        assert_case(DealtHand::new("23432", 20), HandKind::TwoPair);
-        assert_case(DealtHand::new("A23A4", 20), HandKind::OnePair);
-    }
+    use crate::solutions::day7::{categorized_hand::CategorizedHand, dealt_hand::DealtHand};
 
     #[test]
     fn compare_correctly_by_kind_and_second_ordering() {

src/solutions/day7/hand_kind.rs

@@ -1,3 +1,9 @@
+use std::{cmp::Reverse, collections::HashMap};
+
+use log::warn;
+use non_zero_count::NonZeroCount;
+mod non_zero_count;
+
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default)]
 pub enum HandKind {
     /// High card, where all cards' labels are distinct: 23456
@@ -16,3 +22,168 @@ pub enum HandKind {
     /// Five of a kind, where all five cards have the same label: AAAAA
     Five,
 }
+
+impl From<(&'_ str, char)> for HandKind {
+    fn from((characters, joker_char): (&'_ str, char)) -> Self {
+        fn get_joker_count(joker: char, symbols: &str) -> Option<NonZeroCount> {
+            let count = symbols.chars().filter(|&next| next == joker).count();
+            NonZeroCount::new(count)
+        }
+        fn use_jokers(
+            kind: HandKind,
+            how_many_jokers: NonZeroCount,
+        ) -> (HandKind, Option<NonZeroCount>) {
+            match kind {
+                HandKind::HighCard => (HandKind::OnePair, how_many_jokers.decrement()),
+                HandKind::OnePair => (HandKind::Three, how_many_jokers.decrement()),
+                HandKind::TwoPair => (HandKind::FullHouse, how_many_jokers.decrement()),
+                HandKind::Three => (HandKind::Four, how_many_jokers.decrement()),
+                HandKind::FullHouse => (HandKind::Four, how_many_jokers.decrement()),
+                HandKind::Four | HandKind::Five => (HandKind::Five, Some(how_many_jokers)),
+            }
+        }
+
+        let duplicated_counted = calc_duplicate_counted(&characters, |next| next != joker_char);
+
+        let mut current_kind = choose_kind_from(&duplicated_counted);
+        let mut joker_count = get_joker_count(joker_char, characters);
+
+        while joker_count.is_some() && current_kind != HandKind::Five {
+            let (new_kind, new_joker_count) = use_jokers(
+                current_kind,
+                joker_count.expect("While loop only iterates if there is some joke count left"),
+            );
+            current_kind = new_kind;
+            joker_count = new_joker_count;
+        }
+        current_kind
+    }
+}
+
+impl From<&'_ str> for HandKind {
+    fn from(value: &'_ str) -> Self {
+        let duplicated_counted = calc_duplicate_counted(&value, |_| true);
+        choose_kind_from(&duplicated_counted)
+    }
+}
+
+fn calc_duplicate_counted(
+    characters: &str,
+    on_consider_next_char: impl Fn(char) -> bool,
+) -> Vec<usize> {
+    const FIRST_ENCOUNTERED: usize = 1;
+
+    let mut count_of_same: HashMap<char, usize> = HashMap::with_capacity(10);
+
+    for next_char in characters.chars() {
+        if on_consider_next_char(next_char) {
+            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
+    }
+}
+
+fn choose_kind_from(to_choose_from: &[usize]) -> HandKind {
+    fn calc_kind(values: &[usize]) -> Option<HandKind> {
+        let max = values.first()?;
+
+        let kind = match max {
+            5 => HandKind::Five,
+            4 => HandKind::Four,
+            under_five_or_four => {
+                let opt_second_after_max = values.get(1);
+                match opt_second_after_max {
+                    Some(second_after_max) => 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,
+                    },
+                    None => match under_five_or_four {
+                        3 => HandKind::Three,
+                        2 => HandKind::OnePair,
+                        _no_duplicates => HandKind::HighCard,
+                    },
+                }
+            }
+        };
+
+        Some(kind)
+    }
+
+    calc_kind(&to_choose_from).unwrap_or_else(|| {
+        warn!("Got hand ({:?}) with less than 2 cards", &to_choose_from);
+        let default_value = HandKind::default();
+        warn!("Default kind ({:?}) is assumed", default_value);
+        default_value
+    })
+}
+
+#[cfg(test)]
+mod testing {
+    use crate::solutions::day7::{
+        categorized_hand::CategorizedHand, dealt_hand::DealtHand, hand_kind::HandKind,
+    };
+
+    #[test]
+    fn from_dealt_hand_to_categorized_hand() {
+        fn assert_case(given: DealtHand, expected: HandKind) {
+            let expected_hand = CategorizedHand::new(expected, given.clone());
+            let actual = given.into();
+            assert_eq!(expected_hand, actual);
+        }
+        assert_case(DealtHand::new("AAAAA", 20), HandKind::Five);
+        assert_case(DealtHand::new("AA8AA", 20), HandKind::Four);
+        assert_case(DealtHand::new("23332", 20), HandKind::FullHouse);
+        assert_case(DealtHand::new("TTT98", 20), HandKind::Three);
+        assert_case(DealtHand::new("23456", 20), HandKind::HighCard);
+        assert_case(DealtHand::new("23432", 20), HandKind::TwoPair);
+        assert_case(DealtHand::new("A23A4", 20), HandKind::OnePair);
+    }
+
+    #[test]
+    fn from_cards_to_kind_with_joker() {
+        const JOKER: char = 'J';
+        fn assert_case(given: &str, expected: HandKind) {
+            let actual: HandKind = (given, JOKER).into();
+            assert_eq!(expected, actual, "Given: {:?}", given);
+        }
+
+        //32T3K is still the only one pair;
+        //it doesn't contain any jokers, so its strength doesn't increase.
+        assert_case("32T3K", HandKind::OnePair);
+        //KK677 is now the only two pair, making it the second-weakest hand.
+        assert_case("KK677", HandKind::TwoPair);
+        //T55J5, KTJJT, and QQQJA are now all four of a kind! T55J5 gets rank 3,
+        //QQQJA gets rank 4, and KTJJT gets rank 5.
+        assert_case("T55J5", HandKind::Four);
+        assert_case("KTJJT", HandKind::Four);
+        assert_case("QQQJA", HandKind::Four);
+
+        // from highcard
+        assert_case("1234J", HandKind::OnePair);
+        assert_case("123JJ", HandKind::Three);
+        assert_case("12JJJ", HandKind::Four);
+        assert_case("1JJJJ", HandKind::Five);
+        assert_case("JJJJJ", HandKind::Five);
+
+        // from four
+        assert_case("QQQQJ", HandKind::Five);
+        assert_case("QQQQQ", HandKind::Five);
+
+        // from three
+        assert_case("QQQJJ", HandKind::Five);
+
+        // From two pairs
+        assert_case("QQTTJ", HandKind::FullHouse);
+    }
+}

src/solutions/day7/hand_kind/non_zero_count.rs

@@ -0,0 +1,32 @@
+use derive_more::derive::Into;
+
+#[derive(Debug, PartialEq, Eq, Into, Clone, Copy)]
+pub struct NonZeroCount(usize);
+
+impl std::ops::Sub for NonZeroCount {
+    type Output = Option<Self>;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        assert!(self.0 >= rhs.0);
+
+        Self::new(self.0 - rhs.0)
+    }
+}
+
+impl NonZeroCount {
+    pub fn one() -> Self {
+        Self(1)
+    }
+
+    pub fn decrement(&self) -> Option<Self> {
+        *self - Self::one()
+    }
+
+    pub fn new(value: usize) -> Option<Self> {
+        if value > 0 {
+            Some(Self(value))
+        } else {
+            None
+        }
+    }
+}

src/solutions/day7/second_ordering.rs

@@ -2,29 +2,50 @@ use std::{cmp::Ordering, collections::HashMap, ops::RangeInclusive, sync::LazyLo
 
 use log::warn;
 
+const JOKER: char = 'J';
+static LETTERS_WITHOUT_JOKER: &[char] = &['T', 'J', 'Q', 'K', 'A'];
 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
+pub type StrengthOfSymbols = HashMap<char, usize>;
+
+fn numbers_in_chars() -> impl Iterator<Item = char> {
+    NUMBERS
         .into_iter()
-        .map(|number| std::char::from_digit(number, 10).unwrap());
-    numbers
+        .map(|number| std::char::from_digit(number, 10).unwrap())
+}
+
+//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 static LABEL_ORDERING: LazyLock<StrengthOfSymbols> = LazyLock::new(|| {
+    numbers_in_chars()
         .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 {
+
+pub static LABEL_ORDERING_WITH_JOKER: LazyLock<StrengthOfSymbols> = LazyLock::new(|| {
+    std::iter::once(JOKER)
+        .chain(numbers_in_chars())
+        .chain(LETTERS_WITHOUT_JOKER.into_iter().copied())
+        .into_iter()
+        .enumerate()
+        .map(|(index, character)| (character, index))
+        .collect()
+});
+
+pub fn compare_along_str(
+    left: &str,
+    right: &str,
+    symbols_to_strength: &StrengthOfSymbols,
+) -> Ordering {
     for (left_char, right_char) in left.chars().zip(right.chars()) {
-        let left_rank_value = LABEL_ORDERING
+        let left_rank_value = symbols_to_strength
             .get(&left_char)
             .unwrap_or_else(|| panic!("left char ({}) is not valid", left_char));
-        let right_rank_value = LABEL_ORDERING
+        let right_rank_value = symbols_to_strength
             .get(&right_char)
             .unwrap_or_else(|| panic!("right char ({}) is not valid", right_char));