From 0965ff1b6dca8ef6beb0f654716195be68bacdea Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Tue, 6 Dec 2022 21:07:48 +0100
Subject: Add day 2

---
 2022/day2/src/lib.rs | 184 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 184 insertions(+)
 create mode 100644 2022/day2/src/lib.rs

(limited to '2022/day2/src')

diff --git a/2022/day2/src/lib.rs b/2022/day2/src/lib.rs
new file mode 100644
index 0000000..435c8f7
--- /dev/null
+++ b/2022/day2/src/lib.rs
@@ -0,0 +1,184 @@
+enum Player {
+    Rock,
+    Paper,
+    Scissor,
+}
+
+impl Player {
+    fn from_str(c: char) -> Self {
+        match c {
+            'A' | 'X' => Player::Rock,
+            'B' | 'Y' => Player::Paper,
+            'C' | 'Z' => Player::Scissor,
+            _ => panic!("Not valid player!"),
+        }
+    }
+}
+
+struct Play {
+    l: Player,
+    r: Player,
+}
+
+impl Play {
+    fn new(input: &str) -> Self {
+        assert_eq!(input.len(), 3);
+
+        Self {
+            l: Player::from_str(input.chars().nth(0).unwrap()),
+            r: Player::from_str(input.chars().nth(2).unwrap()),
+        }
+    }
+
+    fn points(&self) -> u32 {
+        let mut tot: u32 = 0;
+
+        match self.r {
+            Player::Rock => {
+                tot += 1;
+
+                tot += match self.l {
+                    Player::Rock => 3,
+                    Player::Scissor => 6,
+                    _ => 0,
+                };
+            }
+            Player::Paper => {
+                tot += 2;
+
+                tot += match self.l {
+                    Player::Paper => 3,
+                    Player::Rock => 6,
+                    _ => 0,
+                };
+            }
+            Player::Scissor => {
+                tot += 3;
+
+                tot += match self.l {
+                    Player::Scissor => 3,
+                    Player::Paper => 6,
+                    _ => 0,
+                };
+            }
+        }
+
+        tot
+    }
+
+    fn calc_secret_points(&mut self) {
+        match self.r {
+            // Means "Lose"
+            Player::Rock => {
+                match self.l {
+                    Player::Rock => {
+                        self.r = Player::Scissor;
+                    }
+                    Player::Scissor => {
+                        self.r = Player::Paper;
+                    }
+                    _ => {}
+                };
+            }
+            // Means "Draw"
+            Player::Paper => {
+                match self.l {
+                    Player::Scissor => {
+                        self.r = Player::Scissor;
+                    }
+                    Player::Rock => {
+                        self.r = Player::Rock;
+                    }
+                    _ => {}
+                };
+            }
+            // Means "Win"
+            Player::Scissor => {
+                match self.l {
+                    Player::Scissor => {
+                        self.r = Player::Rock;
+                    }
+                    Player::Rock => {
+                        self.r = Player::Paper;
+                    }
+                    _ => {}
+                };
+            }
+        };
+    }
+}
+
+fn get_plays(input: &str) -> Vec<Play> {
+    input
+        .trim()
+        .split('\n')
+        .collect::<Vec<&str>>()
+        .into_iter()
+        .map(|x| Play::new(x))
+        .collect::<Vec<Play>>()
+}
+
+pub fn part1(input: &str) -> u32 {
+    let mut tot: u32 = 0;
+    let rows = get_plays(input);
+
+    for row in rows {
+        tot += row.points();
+    }
+
+    tot
+}
+
+pub fn part2(input: &str) -> u32 {
+    let mut tot: u32 = 0;
+
+    let mut rows = get_plays(input);
+
+    for row in &mut rows {
+        row.calc_secret_points();
+        tot += row.points();
+    }
+
+    tot
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_example() {
+        let data = include_str!("../example.txt");
+
+        let result = part1(data);
+
+        assert_eq!(result, 15);
+    }
+
+    #[test]
+    fn test_input() {
+        let data = include_str!("../input.txt");
+
+        let result = part1(data);
+
+        assert_eq!(result, 11906);
+    }
+
+    #[test]
+    fn test_example_part2() {
+        let data = include_str!("../example.txt");
+
+        let result = part2(data);
+
+        assert_eq!(result, 12);
+    }
+
+    #[test]
+    fn test_input_part2() {
+        let data = include_str!("../input.txt");
+
+        let result = part2(data);
+
+        assert_eq!(result, 11186);
+    }
+}
-- 
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