add day 8 through 10

day09/src/main.rs

@@ -0,0 +1,68 @@
+use std::collections::HashSet;
+
+use itertools::Itertools;
+
+fn main() {
+    let data = std::fs::read_to_string("input.txt").unwrap();
+    let legs: Vec<_> = data.lines().map(Leg::from_str).collect();
+
+    part1(&legs);
+}
+
+fn part1(legs: &[Leg]) {
+    let mut locations = HashSet::new();
+    for (s, e) in legs.iter().map(|l| (l.from.as_str(), l.to.as_str())) {
+        locations.insert(s);
+        locations.insert(e);
+    }
+
+    let length = locations.len();
+
+    let routes = locations.into_iter().permutations(length).collect_vec();
+
+    let mut sums = vec![];
+
+    for route in routes {
+        let sum: usize = route
+            .iter()
+            .tuple_windows()
+            .map(|(l, r)| find_length(legs, l, r))
+            .sum();
+        sums.push(sum);
+    }
+    sums.sort_unstable();
+    println!("{}\n{}", sums[0], sums.last().unwrap());
+}
+
+fn find_length(legs: &[Leg], a: &str, b: &str) -> usize {
+    for leg in legs {
+        if (leg.from == a || leg.to == a) && (leg.from == b || leg.to == b) {
+            return leg.distance;
+        }
+    }
+    unreachable!()
+}
+
+#[derive(Debug)]
+struct Leg {
+    pub from: String,
+    pub to: String,
+    pub distance: usize,
+}
+
+impl Leg {
+    fn new(from: String, to: String, distance: usize) -> Self {
+        Self { from, to, distance }
+    }
+
+    fn from_str(s: &str) -> Self {
+        let mut segments = s.split_whitespace();
+        let from = segments.next().unwrap().to_string();
+        let to = segments.nth(1).unwrap().to_string();
+        let distance = segments.next_back().unwrap().parse().unwrap();
+
+        Self::new(from, to, distance)
+    }
+}
+
+// https://adventofcode.com/2015/day/9