From cf6303a5bc1558ebdb7b467da38f74cd3ac3a9b1 Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Mon, 5 Dec 2022 19:46:06 +0100
Subject: Add 2022

---
 2021/day10/src/lib.rs | 191 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 191 insertions(+)
 create mode 100644 2021/day10/src/lib.rs

(limited to '2021/day10/src')

diff --git a/2021/day10/src/lib.rs b/2021/day10/src/lib.rs
new file mode 100644
index 0000000..6cf54ad
--- /dev/null
+++ b/2021/day10/src/lib.rs
@@ -0,0 +1,191 @@
+use std::collections::VecDeque;
+use std::str::FromStr;
+
+pub struct SyntaxLines {
+    lines: Vec<String>,
+}
+
+impl FromStr for SyntaxLines {
+    type Err = ();
+
+    fn from_str(input: &str) -> Result<Self, Self::Err> {
+        let lines: Vec<_> = input
+            .trim()
+            .split('\n')
+            .map(|x| x.to_owned())
+            .collect::<Vec<String>>();
+
+        Ok(SyntaxLines { lines })
+    }
+}
+
+impl SyntaxLines {
+    pub fn part1(&self) -> u32 {
+        let mut result: u32 = 0;
+
+        for line in &self.lines {
+            let mut qopen = VecDeque::new();
+            let mut panic_char = ' ';
+
+            for character in line.chars() {
+                match character {
+                    c if character == '('
+                        || character == '['
+                        || character == '{'
+                        || character == '<' =>
+                    {
+                        qopen.push_back(c);
+                    }
+                    c if character == ')'
+                        || character == ']'
+                        || character == '}'
+                        || character == '>' =>
+                    {
+                        match qopen.pop_back() {
+                            Some(bracket) => {
+                                let mut error = false;
+                                if c == ')' && bracket != '(' {
+                                    error = true;
+                                } else if c == ']' && bracket != '[' {
+                                    error = true;
+                                } else if c == '}' && bracket != '{' {
+                                    error = true;
+                                } else if c == '>' && bracket != '<' {
+                                    error = true;
+                                }
+
+                                if error {
+                                    panic_char = c;
+                                }
+                            }
+                            None => panic!("Wtf?"),
+                        };
+                    }
+                    _ => {}
+                };
+
+                if panic_char != ' ' {
+                    if panic_char == ')' {
+                        result += 3;
+                    } else if panic_char == ']' {
+                        result += 57;
+                    } else if panic_char == '}' {
+                        result += 1197;
+                    } else if panic_char == '>' {
+                        result += 25137;
+                    }
+                    break;
+                }
+            }
+        }
+
+        result
+    }
+
+    pub fn part2(&self) -> u64 {
+        let mut scores = Vec::<u64>::new();
+
+        for line in &self.lines {
+            let mut qopen = VecDeque::new();
+            let mut panic_char = ' ';
+            let mut result: u64 = 0;
+
+            for character in line.chars() {
+                match character {
+                    c if character == '('
+                        || character == '['
+                        || character == '{'
+                        || character == '<' =>
+                    {
+                        qopen.push_back(c);
+                    }
+                    c if character == ')'
+                        || character == ']'
+                        || character == '}'
+                        || character == '>' =>
+                    {
+                        match qopen.pop_back() {
+                            Some(bracket) => {
+                                let mut error = false;
+                                if c == ')' && bracket != '(' {
+                                    error = true;
+                                } else if c == ']' && bracket != '[' {
+                                    error = true;
+                                } else if c == '}' && bracket != '{' {
+                                    error = true;
+                                } else if c == '>' && bracket != '<' {
+                                    error = true;
+                                }
+
+                                if error {
+                                    panic_char = c;
+                                }
+                            }
+                            None => panic!("Wtf?"),
+                        };
+                    }
+                    _ => {}
+                };
+
+                if panic_char != ' ' {
+                    break;
+                }
+            }
+
+            if panic_char == ' ' {
+                while !qopen.is_empty() {
+                    let v = qopen.pop_back().unwrap();
+                    result *= 5;
+                    result += if v == '(' {
+                        1
+                    } else if v == '[' {
+                        2
+                    } else if v == '{' {
+                        3
+                    } else {
+                        4
+                    };
+                }
+                scores.push(result);
+            }
+        }
+
+        let middle = scores.len() / 2 as usize;
+        scores.sort();
+
+        scores[middle]
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_example() {
+        let input: SyntaxLines = include_str!("../example.txt").parse().unwrap();
+        let result = input.part1();
+        assert_eq!(result, 26397);
+    }
+
+    #[test]
+    fn test_example_part2() {
+        let input: SyntaxLines = include_str!("../example.txt").parse().unwrap();
+        let result = input.part2();
+        assert_eq!(result, 288957);
+    }
+
+    #[test]
+    fn test_puzzle_input() {
+        let input: SyntaxLines = include_str!("../input.txt").parse().unwrap();
+        let result = input.part1();
+        assert_eq!(result, 392367);
+    }
+
+    #[test]
+    fn test_puzzle_input_part2() {
+        let input: SyntaxLines = include_str!("../input.txt").parse().unwrap();
+        let result = input.part2();
+        assert_eq!(result, 2192104158);
+    }
+}
-- 
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