Add day 2

2021/src/bin/day02.rs

@@ -0,0 +1,71 @@
+#![feature(test)]
+extern crate test;
+use aoc2021::common::*;
+
+#[derive(Debug, Clone, Copy)]
+enum Movement {
+    Up(i64),
+    Down(i64),
+    Forward(i64),
+}
+
+type Parsed = Vec<Movement>;
+
+fn read_input() -> String {
+    read_file(2)
+}
+
+fn parse_input(raw: &str) -> Parsed {
+    raw.lines()
+        .filter_map(|l| l.split_once(' '))
+        .map(|(dir, dist)| match dir {
+            "up" => Movement::Up(dist.parse().unwrap()),
+            "down" => Movement::Down(dist.parse().unwrap()),
+            "forward" => Movement::Forward(dist.parse().unwrap()),
+            _ => unreachable!(),
+        })
+        .collect()
+}
+
+fn part1(parsed: &Parsed) -> i64 {
+    let (depth, distance) = parsed.iter().fold((0, 0), |(depth, distance), &mov| match mov {
+        Movement::Up(x) => (depth - x, distance),
+        Movement::Down(x) => (depth + x, distance),
+        Movement::Forward(x) => (depth, distance + x),
+    });
+    depth * distance
+}
+
+fn part2(parsed: &Parsed) -> i64 {
+    let (depth, distance, _) = parsed.iter().fold((0, 0, 0), |(depth, distance, aim), &mov| match mov {
+        Movement::Up(x) => (depth, distance, aim - x),
+        Movement::Down(x) => (depth, distance, aim + x),
+        Movement::Forward(x) => (depth + aim * x, distance + x, aim),
+    });
+    depth * distance
+}
+
+fn main() {
+    let input = parse_input(&read_input());
+    println!("Part 1: {}", part1(&input));
+    println!("Part 2: {}", part2(&input));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use aoc2021::*;
+
+    const TEST_INPUT: &str = "forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2";
+
+    test!(part1() == 150);
+    test!(part2() == 900);
+    bench!(part1() == 1698735);
+    bench!(part2() == 1594785890);
+    bench_input!(len == 1000);
+}