add code for 84 (WIP)

src/euler84/Cargo.toml

@@ -7,3 +7,5 @@ edition = "2021"
 
 [dependencies]
 rand = "0.8.5"
+strum = "0.24.1"
+strum_macros = "0.24.1"

src/euler84/src/lib.rs

@@ -1,7 +1,15 @@
+use std::collections::{HashMap, VecDeque};
+use std::iter::Cycle;
+
 use rand::prelude::*;
 use rand::seq::IteratorRandom;
+use strum::IntoEnumIterator;
+use strum_macros::EnumIter;
 
-enum Squares {
+const NUMBER_SQUARES: usize = 40;
+
+#[derive(Debug, EnumIter, PartialEq, Hash, Eq, PartialOrd)]
+pub enum Squares {
     Go = 0,
     A1 = 1,
     CC1 = 2,
@@ -9,7 +17,7 @@ enum Squares {
     T1 = 4,
     R1 = 5,
     B1 = 6,
-    Ch1 = 7,
+    CH1 = 7,
     B2 = 8,
     B3 = 9,
     Jail = 10,
@@ -24,7 +32,7 @@ enum Squares {
     D3 = 19,
     FP = 20,
     E1 = 21,
-    Ch2 = 22,
+    CH2 = 22,
     E2 = 23,
     E3 = 24,
     R3 = 25,
@@ -32,10 +40,10 @@ enum Squares {
     F2 = 27,
     U2 = 28,
     F3 = 29,
-    G2j = 30,
+    G2J = 30,
     G1 = 31,
     G2 = 32,
-    Cc3 = 33,
+    CC3 = 33,
     G3 = 34,
     R4 = 35,
     Ch3 = 36,
@@ -44,11 +52,13 @@ enum Squares {
     H2 = 39,
 }
 
+#[derive(Debug, EnumIter, Clone)]
 enum CommunityChest {
     AdvanceToGo,
     GoToJail,
 }
 
+#[derive(Debug, EnumIter, Clone)]
 enum Chance {
     AdvanceToGo,
     GoToJail,
@@ -62,28 +72,194 @@ enum Chance {
     GoBack3Squares,
 }
 
+#[derive(Debug)]
 enum Dice {
     FourSided = 4,
     SixSided = 6,
 }
 
 impl Dice {
-    fn throw(&self, rng: &mut ThreadRng) -> isize {
+    fn throw(&self, rng: &mut ThreadRng) -> usize {
         match self {
-            Self::SixSided => (1..=6).choose(rng).unwrap(),
-            Self::FourSided => (1..=4).choose(rng).unwrap(),
+            Self::SixSided => (1..=6).choose(rng).unwrap() as usize,
+            Self::FourSided => (1..=4).choose(rng).unwrap() as usize,
         }
     }
 }
 
-struct Monopoly {
-    position: Squares,
+pub struct Monopoly {
+    rng: ThreadRng,
+    board: Cycle<SquaresIter>,
     dice: Dice,
+    community_pile: VecDeque<CommunityChest>,
+    chance_pile: VecDeque<Chance>,
+    number_consecutive_doubles: usize,
 }
 
 impl Monopoly {
-    fn throw_dice(&mut self) {
+    fn throw_dice(&mut self) -> (usize, bool) {
+        let mut iter = (0..2).map(|_| self.dice.throw(&mut self.rng));
+        let t1 = iter.next().unwrap();
+        let t2 = iter.next().unwrap();
+        let is_double = t1 == t2;
+        // dbg!(t1, t2);
+        (t1 + t2, is_double)
+    }
+
+    #[allow(clippy::new_without_default)]
+    pub fn new() -> Self {
         let mut rng = rand::thread_rng();
-        let result: isize = (0..2).map(|_| self.dice.throw(&mut rng)).sum();
+        let community_pile = Self::gen_random_community_pile(&mut rng);
+        let chance_pile = Self::gen_random_chance_pile(&mut rng);
+        Self {
+            rng,
+            board: Squares::iter().cycle(),
+            dice: Dice::SixSided,
+            community_pile,
+            chance_pile,
+            number_consecutive_doubles: 0,
+        }
+    }
+
+    fn gen_random_chance_pile(rng: &mut ThreadRng) -> VecDeque<Chance> {
+        let mut instances: Vec<_> = Chance::iter().collect();
+        instances.shuffle(rng);
+        instances.into()
+    }
+
+    fn gen_random_community_pile(rng: &mut ThreadRng) -> VecDeque<CommunityChest> {
+        let mut instances: Vec<_> = CommunityChest::iter().collect();
+        instances.shuffle(rng);
+        instances.into()
+    }
+
+    #[must_use]
+    pub fn make_move(&mut self) -> Squares {
+        let (distance, is_double) = self.throw_dice();
+        if self.check_too_many_doubles(is_double) {
+            return self.go_to_jail();
+        }
+
+        let square = self.board.nth(distance).unwrap();
+        match square {
+            Squares::G2J => self.go_to_jail(),
+            Squares::CC1 | Squares::CC2 | Squares::CC3 => self.handle_community_chest(),
+            Squares::CH1 | Squares::CH2 => self.handle_chance(),
+            _ => square,
+        }
+    }
+
+    fn go_to_jail(&mut self) -> Squares {
+        let _ = (&mut self.board).skip_while(|c| *c != Squares::Jail);
+        Squares::Jail
+    }
+
+    fn handle_chance(&mut self) -> Squares {
+        let card = self.draw_from_chance_pile_and_put_at_bottom();
+        // dbg!(card);
+        match card {
+            Chance::AdvanceToGo => self.advance_to_go(),
+            Chance::GoToJail => self.go_to_jail(),
+            Chance::GoToC1 => self.go_to_square(Squares::C1),
+            Chance::GoToE3 => self.go_to_square(Squares::E3),
+            Chance::GoToH2 => self.go_to_square(Squares::H2),
+            Chance::GoToR1 => self.go_to_square(Squares::R1),
+            Chance::GoToNextR | Chance::GoToNextRAgain => self.go_to_railway(),
+            Chance::GoToNextU => self.go_to_utility(),
+            Chance::GoBack3Squares => self.go_back_3_squares(),
+        }
+    }
+
+    fn go_to_square(&mut self, square: Squares) -> Squares {
+        let _ = (&mut self.board).skip_while(|c| *c != square);
+        square
+    }
+
+    fn go_to_squares(&mut self, squares: &[Squares]) -> Squares {
+        let result = self.board.find(|c| squares.iter().any(|s| s == c)).unwrap();
+        assert!(squares.contains(&result));
+        result
+    }
+
+    fn handle_community_chest(&mut self) -> Squares {
+        let card = self.draw_from_community_chest_pile_and_put_at_bottom();
+        match card {
+            CommunityChest::AdvanceToGo => self.advance_to_go(),
+            CommunityChest::GoToJail => self.go_to_jail(),
+        }
+    }
+
+    fn advance_to_go(&mut self) -> Squares {
+        let _ = (&mut self.board).skip_while(|c| *c != Squares::Go);
+        Squares::Go
+    }
+
+    fn draw_from_chance_pile_and_put_at_bottom(&mut self) -> &Chance {
+        let card = self.chance_pile.pop_front().unwrap();
+        self.chance_pile.push_back(card);
+        self.chance_pile.back().unwrap()
+    }
+
+    fn draw_from_community_chest_pile_and_put_at_bottom(&mut self) -> &CommunityChest {
+        let card = self.community_pile.pop_front().unwrap();
+        self.community_pile.push_back(card);
+        self.community_pile.back().unwrap()
+    }
+
+    fn go_to_railway(&mut self) -> Squares {
+        self.go_to_squares(&[Squares::R1, Squares::R2, Squares::R3, Squares::R4])
+    }
+
+    fn go_to_utility(&mut self) -> Squares {
+        self.go_to_squares(&[Squares::U1, Squares::U2])
+    }
+
+    fn go_back_3_squares(&mut self) -> Squares {
+        self.board.nth(NUMBER_SQUARES - 3).unwrap()
+    }
+
+    fn check_too_many_doubles(&mut self, is_double: bool) -> bool {
+        if is_double {
+            self.number_consecutive_doubles += 1;
+            self.number_consecutive_doubles == 3
+        } else {
+            self.number_consecutive_doubles = 0;
+            false
+        }
+    }
+}
+
+pub struct Statistics {
+    monopoly: Monopoly,
+    iterations: usize,
+    fields_count: HashMap<Squares, usize>,
+}
+
+impl Statistics {
+    pub fn new(monopoly: Monopoly, iterations: usize) -> Self {
+        Self {
+            monopoly,
+            iterations,
+            fields_count: HashMap::from_iter(Squares::iter().zip([0].into_iter().cycle())),
+        }
+    }
+
+    pub fn run(&mut self) {
+        for _ in 0..self.iterations {
+            let square = self.monopoly.make_move();
+            *self.fields_count.get_mut(&square).unwrap() += 1;
+        }
+    }
+
+    pub fn show(&self) {
+        let mut result: Vec<(&Squares, f64)> = self
+            .fields_count
+            .iter()
+            .map(|(k, v)| (k, *v as f64 / self.iterations as f64 * 100.))
+            .collect();
+        result.sort_unstable_by(|(_, v1), (_, v2)| v2.partial_cmp(v1).unwrap());
+        for (s, v) in result {
+            println!("{s:?}: {v}");
+        }
     }
 }

src/euler84/src/main.rs

@@ -1,3 +1,8 @@
+mod lib;
+
 fn main() {
-    println!("Hello, world!");
+    let monopoly = lib::Monopoly::new();
+    let mut statistics = lib::Statistics::new(monopoly, 100_000);
+    statistics.run();
+    statistics.show();
 }