feat: add day 9

src/bin/09.rs

@@ -0,0 +1,88 @@
+advent_of_code::solution!(9);
+
+fn count_uncompressed_length(input: &str, with_recursion: bool) -> usize {
+    let mut chars = input.chars().peekable();
+    let mut count: usize = 0;
+
+    while let Some(c) = chars.next() {
+        match c {
+            '(' => {
+                // Fetch marker
+                let inner = chars.clone().take_while(|c| *c != ')').collect::<String>();
+
+                // Skip marker
+                for _ in 0..(inner.len() + 1) {
+                    chars.next();
+                }
+
+                // Parse marker
+                let inner: Vec<usize> = inner
+                    .split("x")
+                    .map(|s| s.parse::<usize>().unwrap())
+                    .collect();
+                if inner.len() < 2 {
+                    panic!("invalid input");
+                }
+
+                // Fetch repeated string
+                let repeated = chars.clone().take(inner[0]).collect::<String>();
+                let repeated_length: usize = if with_recursion {
+                    count_uncompressed_length(&repeated.to_string(), with_recursion)
+                } else {
+                    repeated.len()
+                };
+
+                // Add repeated to the count and skip it
+                count += repeated_length * inner[1];
+                for _ in 0..(inner[0]) {
+                    chars.next();
+                }
+            }
+            ')' => {
+                println!("Found closing parent (?!)");
+            }
+            ' ' => (),
+            _ => count += 1,
+        }
+    }
+    count
+}
+
+pub fn part_one(input: &str) -> Option<usize> {
+    let input = input.strip_suffix("\n").unwrap_or(input);
+    count_uncompressed_length(input, false).into()
+}
+
+pub fn part_two(input: &str) -> Option<usize> {
+    let input = input.strip_suffix("\n").unwrap_or(input);
+    count_uncompressed_length(input, true).into()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        // let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        // assert_eq!(result, None);
+        assert_eq!(part_one("ADVENT"), Some(6));
+        assert_eq!(part_one("A(1x5)BC"), Some(7));
+        assert_eq!(part_one("A(2x2)BCD(2x2)EFG"), Some(11));
+        assert_eq!(part_one("(6x1)(1x3)A"), Some(6));
+        assert_eq!(part_one("X(8x2)(3x3)ABCY"), Some(18));
+        // assert_eq!(part_one("X(8x2)(3x3)A BCY"), Some(18));
+    }
+
+    #[test]
+    fn test_part_two() {
+        // let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        // assert_eq!(result, None);
+        assert_eq!(part_two("ADVENT"), Some(6));
+        assert_eq!(part_two("A(1x5)BC"), Some(7));
+        assert_eq!(part_two("A(2x2)BCD(2x2)EFG"), Some(11));
+        assert_eq!(part_two("(6x1)(1x3)A"), Some(3));
+        assert_eq!(part_two("X(8x2)(3x3)ABCY"), Some(20));
+        assert_eq!(part_two("(27x12)(20x12)(13x14)(7x10)(1x12)A"), Some(241920));
+    }
+}