From 6e10cc2773fcaff64902b13f44443da014f38be7 Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Tue, 14 Dec 2021 21:31:50 +0100
Subject: Add part2 of day10

---
 day10/src/lib.rs | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)

(limited to 'day10')

diff --git a/day10/src/lib.rs b/day10/src/lib.rs
index f483420..6cf54ad 100644
--- a/day10/src/lib.rs
+++ b/day10/src/lib.rs
@@ -81,6 +81,80 @@ impl SyntaxLines {
 
         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)]
@@ -94,10 +168,24 @@ mod tests {
         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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