solution: day 1

src/days.rs

@@ -1,3 +1,4 @@
+pub mod d1;
 // pub mod d2;
 // pub mod d3;
 // pub mod d4;

src/days/d1.rs

@@ -0,0 +1,57 @@
+use crate::prelude::*;
+
+pub type I = (Vec<u32>, Vec<u32>);
+pub type O = u32;
+
+fn _parse (data: &str) -> I {
+    let (mut l, mut r) = (vec![], vec![]);
+    data.lines().for_each(|line| {
+        let mut iter = line.split_whitespace();
+
+        let left = p!(n!(iter));
+        let right = p!(n!(iter));
+        l.push(left);
+        r.push(right);
+    });
+
+    (l, r)
+}
+
+fn _silver ((mut left, mut right): I) -> O {
+    left.sort();
+    right.sort();
+
+    left.into_iter().zip(right.into_iter()).fold(0, |acc, (l, r)| acc + l.abs_diff(r))
+}
+
+fn _gold ((left, right): I) -> O {
+    let right = right.into_iter().counts();
+
+    left.into_iter().fold(0, |acc, cur| acc + cur * *right.get(&cur).unwrap_or(&0) as u32)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    fn read () -> I {
+        let data = inc!(1);
+        _parse(data)
+    }
+
+    #[test]
+    fn silver () {
+        let data = read();
+        let ans = _silver(data);
+
+        assert_eq!(ans, 2196996)
+    }
+
+    #[test]
+    fn gold () {
+        let data = read();
+        let ans = _gold(data);
+
+        assert_eq!(ans, 23655822)
+    }
+}