day-13 done without clippy or format

2023/day-13/src/part2.rs

@@ -1,20 +1,151 @@
 #![warn(clippy::all, clippy::pedantic)]
 
+use std::collections::HashSet;
+
+use glam::UVec2;
+use nom::{
+    bytes::complete::is_a,
+    character::complete,
+    multi::separated_list1,
+    IResult, sequence::tuple,
+};
+
+struct Drawing {
+    pub size: UVec2,
+    pub mounds: HashSet<UVec2>,
+}
+
+impl Drawing {
+    fn process(&self) -> u32 {
+        let (max_col, max_row) = self.size.into();
+        let col_score = (1..max_col )
+            .filter_map(|reflect_col| {
+                let span = reflect_col.min(max_col - reflect_col);
+                ((self.mounds
+                    .iter()
+                    .filter(|mound| mound.x + span >= reflect_col && mound.x < reflect_col)
+                    .map(|mound| (2* reflect_col - mound.x  - 1, mound.y).into())
+                    .filter(|mound_reflect| self.mounds.get(&mound_reflect).is_none())
+                    .count() 
+                    +
+                self.mounds
+                    .iter()
+                    .filter(|mound|mound.x < reflect_col + span && mound.x >= reflect_col)
+                    .map(|mound| ( 2*reflect_col - mound.x - 1,mound.y).into())
+                    .filter(|mound_reflect| self.mounds.get(&mound_reflect).is_none())
+                    .count()
+                ) == 1)
+                    .then_some(reflect_col)
+            })
+            .sum::<u32>();
+        let row_score = (1..max_row )
+            .filter_map(|reflect_row| {
+                let span = reflect_row.min(max_row - reflect_row);
+                ((self.mounds
+                    .iter()
+                    .filter(|mound| mound.y + span >= reflect_row && mound.y < reflect_row)
+                    .map(|mound| (mound.x, 2 * reflect_row - mound.y - 1).into())
+                    .filter(|mound_reflect| self.mounds.get(&mound_reflect).is_none())
+                    .count()
+                    +
+                self.mounds
+                    .iter()
+                    .filter(|mound|mound.y < reflect_row + span && mound.y >= reflect_row)
+                    .map(|mound| (mound.x, 2*reflect_row - mound.y - 1).into())
+                    .filter(|mound_reflect| self.mounds.get(&mound_reflect).is_none())
+                    .count()
+                    ) == 1 )
+                    .then_some(reflect_row)
+            })
+            .sum::<u32>()
+            * 100;
+        col_score + row_score
+    }
+}
+
 #[must_use]
-pub fn part2 (_input: &str) -> String {
-    "Not Finished".to_string()
+pub fn part2(_input: &str) -> String {
+    let (_, drawings) = parse_input(_input).expect("aoc always valid");
+    drawings.iter().map(Drawing::process).sum::<u32>().to_string()
+}
+
+fn parse_drawing(input: &str) -> IResult<&str, Drawing> {
+    let (input, rows) = separated_list1(complete::line_ending, is_a(".#"))(input)?;
+    let max_rows = u32::try_from(rows.len()).expect("shouldn't be that big");
+    let max_cols = u32::try_from(rows[0].len()).expect("shouldn't be that big");
+    let size = UVec2::from((max_cols, max_rows));
+    let mounds = rows
+        .iter()
+        .enumerate()
+        .flat_map(|y| {
+            y.1.chars().enumerate().map(move |x| {
+                (
+                    u32::try_from(x.0).expect("should be 32"),
+                    u32::try_from(y.0).expect("should not fail"),
+                    x.1,
+                )
+            })
+        })
+        .filter_map(|(x, y, mound)| (mound == '#').then_some(UVec2::from((x, y)) ))
+        .collect();
+    Ok((input, Drawing { size, mounds }))
+}
+
+fn parse_input(input: &str) -> IResult<&str, Vec<Drawing>>{
+    separated_list1(tuple((complete::line_ending, complete::line_ending)), parse_drawing)(input)
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
+    use rstest::rstest;
 
-    const INPUT: &str = "";
+    #[rstest]
+    #[case(
+        "#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.",
+        300
+    )]
+    #[case(
+        "#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#",
+        100
+    )]
+    fn board_test(#[case] input: &str, #[case] expected: u32) {
+        let (_, drawing) = parse_drawing(input).expect("Parsing should work");
+        assert_eq!(drawing.process(), expected);
+    }
+
+    const INPUT: &str = "#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#";
 
     #[test]
     fn part2_works() {
         let result = part2(INPUT);
-        assert_eq!(result, "Not Finished".to_string());
+        assert_eq!(result, "400".to_string());
     }
 }