solution: day 10

src/days.rs

@@ -7,7 +7,7 @@ pub mod d6;
 pub mod d7;
 pub mod d8;
 pub mod d9;
-// pub mod d10;
+pub mod d10;
 // pub mod d11;
 // pub mod d12;
 // pub mod d13;

src/days/d10.rs

@@ -0,0 +1,103 @@
+use crate::prelude::*;
+
+pub type I1 = Vec<Vec<char>>;
+pub type I2 = Vec<(usize, usize)>;
+pub type O = usize;
+
+fn _parse (data: &str) -> (I1, I2) {
+    data.trim().lines().enumerate().fold((vec![], vec![]), |(mut map, mut zeroes), (y, line)| {
+        let mut l = vec![];
+        for (x, c) in line.trim().chars().enumerate() {
+            l.push(c);
+            if c == '0' { zeroes.push((y, x)); }
+        }
+        map.push(l);
+        (map, zeroes)
+    })
+}
+
+fn _dfs (
+    pos @ (y, x): (usize, usize),
+    map: &[Vec<char>],
+    visited: &mut S<(usize, usize)>,
+    silver: &mut S<(usize, usize)>,
+    gold: &mut O,
+) {
+    visited.insert(pos);
+
+    let current = map[y][x];
+    if current == '9' {
+        silver.insert(pos);
+        *gold += 1;
+        return;
+    }
+
+    let neighbors = [(-1, 0), (0, -1), (0, 1), (1, 0)].into_iter().filter_map(|(dy, dx)| match (y.checked_add_signed(dy), x.checked_add_signed(dx)) {
+        (Some(y), Some(x)) if y < map.len() && x < map[0].len() => Some((y, x)),
+        _ => None
+    }).filter(|&(y, x)| map[y][x] as u8 - current as u8 == 1);
+
+
+    let cloned = visited.clone();
+
+    for n in neighbors {
+        if !visited.contains(&n) {
+            _dfs(n, map, visited, silver, gold);
+        }
+        *visited = cloned.clone();
+    }
+}
+
+fn _solve ((map, zeroes): &(I1, I2)) -> (O, O) {
+    let (mut silver, mut gold) = (0, 0);
+
+    for &z in zeroes {
+        let mut _sm = S::new();
+        _dfs(z, &map, &mut S::new(), &mut _sm, &mut gold);
+        silver += _sm.len();
+    }
+    (silver, gold)
+}
+
+fn _silver (i: &(I1, I2)) -> O {
+    _solve(i).0
+}
+
+fn _gold (i: &(I1, I2)) -> O {
+    _solve(i).1
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    fn read () -> (I1, I2) {
+        let data = inc!(10);
+        _parse(data)
+    }
+
+    #[test]
+    fn sample () {
+        let data = inc!("10_example");
+        let data = _parse(data);
+
+        assert_eq!(_silver(&data), 36);
+        assert_eq!(_gold(&data), 81);
+    }
+
+    #[test]
+    fn silver () {
+        let data = read();
+        let ans = _silver(&data);
+
+        assert_eq!(ans, 694)
+    }
+
+    #[test]
+    fn gold () {
+        let data = read();
+        let ans = _gold(&data);
+
+        assert_eq!(ans, 1497)
+    }
+}