chore: refactor for cargo-aoc / codspeed

src/day4.rs

@@ -0,0 +1,145 @@
+use aoc_runner_derive::{aoc, aoc_generator};
+use std::io::{BufRead, Lines};
+
+#[aoc_generator(day4)]
+pub fn get_input(input: &[u8]) -> WordSearch {
+    WordSearch::from(input.lines())
+}
+
+pub struct WordSearch {
+    rows: Vec<String>,
+}
+
+impl<T: BufRead> From<Lines<T>> for WordSearch {
+    fn from(input: Lines<T>) -> Self {
+        let mut rows = Vec::new();
+        for line in input.map(|i| i.unwrap()) {
+            rows.push(line);
+        }
+        Self { rows }
+    }
+}
+
+impl WordSearch {
+    fn count_occurences(haystack: &str, needle: &str) -> u64 {
+        let mut count = 0;
+        for start in 0..haystack.len() - needle.len() + 1 {
+            if &haystack[start..start + needle.len()] == needle {
+                count += 1;
+            }
+        }
+        count
+    }
+    fn count_forward(&self, needle: &str) -> u64 {
+        let mut count = 0;
+        for row in &self.rows {
+            count += Self::count_occurences(row, needle)
+        }
+        count
+    }
+    fn count_vertical(&self, needle: &str) -> u64 {
+        let mut count = 0;
+        for col in 0..self.rows[0].len() {
+            let s: String = self.rows.iter().map(|row| row.as_bytes()[col] as char).collect();
+            count += Self::count_occurences(&s, needle)
+        }
+        count
+    }
+    fn count_diagonal(&self, needle: &str) -> u64 {
+        let width = self.rows[0].len();
+        let height = self.rows.len();
+
+        let mut count = 0;
+        for x in 0..width {
+            for y in 0..height {
+                // check down-right
+                if x <= width - needle.len() && y <= height - needle.len() && (0..needle.len()).all(|i| self.get(x + i, y + i) == needle.as_bytes()[i].into()) {
+                    count += 1
+                }
+                // check down-left
+                if x >= needle.len() - 1 && y <= height - needle.len() && (0..needle.len()).all(|i| self.get(x - i, y + i) == needle.as_bytes()[i].into()) {
+                    count += 1
+                }
+            }
+        }
+        count
+    }
+
+    fn get(&self, x: usize, y: usize) -> char {
+        self.rows[y].as_bytes()[x].into()
+    }
+
+    fn count_x_mas(&self) -> u64 {
+        // M.M M.S S.M S.S
+        // .A. .A. .A. .A.
+        // S.S M.S S.M M.M
+        let searches: [[char; 5]; 4] =
+            ["MMASS", "MSAMS", "SMASM", "SSAMM"].map(|s| s.chars().collect::<Vec<char>>().try_into().unwrap());
+        let width = self.rows[0].len();
+        let height = self.rows.len();
+
+        let mut count = 0;
+        for x in 0..width - 2 {
+            for y in 0..height - 2 {
+                let s = [
+                    self.get(x, y),
+                    self.get(x + 2, y),
+                    self.get(x + 1, y + 1),
+                    self.get(x, y + 2),
+                    self.get(x + 2, y + 2),
+                ];
+                for needle in &searches {
+                    if needle == &s {
+                        count += 1
+                    }
+                }
+            }
+        }
+        count
+    }
+}
+
+// PROBLEM 1 solution
+#[aoc(day4, part1)]
+pub fn part1(ws: &WordSearch) -> u64 {
+    let needle = "XMAS";
+    let needle_rev: String = needle.chars().rev().collect();
+    ws.count_forward(needle)
+        + ws.count_forward(&needle_rev)
+        + ws.count_vertical(needle)
+        + ws.count_vertical(&needle_rev)
+        + ws.count_diagonal(needle)
+        + ws.count_diagonal(&needle_rev)
+}
+
+// PROBLEM 2 solution
+#[aoc(day4, part2)]
+pub fn part2(ws: &WordSearch) -> u64 {
+    ws.count_x_mas()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::day4::*;
+
+    const EXAMPLE: &[u8] = b"MMMSXXMASM
+MSAMXMSMSA
+AMXSXMAAMM
+MSAMASMSMX
+XMASAMXAMM
+XXAMMXXAMA
+SMSMSASXSS
+SAXAMASAAA
+MAMMMXMMMM
+MXMXAXMASX";
+
+    #[test]
+    fn part1_example() {
+        assert_eq!(part1(&get_input(EXAMPLE)), 18);
+    }
+
+    #[test]
+    fn part2_example() {
+        assert_eq!(part2(&get_input(EXAMPLE)), 9);
+    }
+}