solution: day 7

src/days.rs

@@ -4,7 +4,7 @@ pub mod d3;
 pub mod d4;
 pub mod d5;
 pub mod d6;
-// pub mod d7;
+pub mod d7;
 // pub mod d8;
 // pub mod d9;
 // pub mod d10;

src/days/d7.rs

@@ -0,0 +1,81 @@
+use crate::prelude::*;
+
+pub type I = Vec<(SS, Vec<SS>, Vec<SS>)>;
+pub type O = usize;
+
+fn _parse (data: &'static str) -> I {
+    data.lines().map(|line| {
+        let line = line.trim();
+        let mut out = vec![];
+        let mut _in = vec![];
+        let mut pos = false;
+
+        let mut l = 0;
+        let mut r = 0;
+
+        for (idx, c) in line.char_indices() {
+
+            match c {
+                '[' | ']' => {
+                    let v = if pos { &mut _in } else { &mut out };
+                    v.push(&line[l..r]);
+                    pos = !pos;
+                    l = idx + 1;
+                    r = l;
+                    continue;
+                },
+                _ => {
+                    r += 1;
+                }
+            }
+        }
+
+        let v = if pos { &mut _in } else { &mut out };
+        v.push(&line[l..r]);
+
+        (line, _in, out)
+    }).collect()
+}
+
+fn _silver (data: &I) -> O {
+    let abba = |(a, b, c, d)| a == d && b == c && b != a;
+    data.into_iter().filter(|(_, _in, out)| {
+        !_in.into_iter().any(|part| part.chars().tuple_windows().any(abba)) &&
+        out.into_iter().any(|part| part.chars().tuple_windows().any(abba))
+    }).count()
+}
+
+fn _gold (data: &I) -> O {
+    let aba = |(a, b, c)| a == c && b != a;
+    data.into_iter().filter(|(_, _in, out)| {
+        let mut abas = S::new();
+        out.into_iter().for_each(|part| part.chars().tuple_windows().for_each(|x| if aba(x) { abas.insert(x); }));
+        _in.into_iter().any(|part| part.chars().tuple_windows().any(|x @ (a, b, _)| aba(x) && abas.contains(&(b, a, b))))
+    }).count()
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    fn read () -> I {
+        let data = inc!(7);
+        _parse(data)
+    }
+
+    #[test]
+    fn silver () {
+        let data = read();
+        let ans = _silver(&data);
+
+        assert_eq!(ans, 105)
+    }
+
+    #[test]
+    fn gold () {
+        let data = read();
+        let ans = _gold(&data);
+
+        assert_eq!(ans, 258)
+    }
+}