2021: day01 part 1 & part 2

aoc2021/src/day01.rs

@@ -0,0 +1,45 @@
+use std::fmt::Write;
+
+use anyhow::Result;
+
+const INPUT: &str = include_str!("../input/day01.txt");
+
+pub fn run() -> Result<String> {
+    let mut res = String::with_capacity(128);
+
+    writeln!(res, "part 1: {}", part1(INPUT)?)?;
+    writeln!(res, "part 2: {}", part2(INPUT)?)?;
+
+    Ok(res)
+}
+
+fn part1(input: &str) -> Result<usize> {
+    let measurements = input
+        .lines()
+        .map(|line| line.parse::<u64>().map_err(anyhow::Error::new))
+        .collect::<Result<Vec<_>>>()?;
+
+    Ok(measurements.windows(2).filter(|w| w[0] < w[1]).count())
+}
+
+fn part2(input: &str) -> Result<usize> {
+    let measurements = input
+        .lines()
+        .map(|line| line.parse::<u64>().map_err(anyhow::Error::new))
+        .collect::<Result<Vec<_>>>()?;
+
+    let mut increases = 0;
+    let mut prev: Option<u64> = None;
+
+    for window in measurements.windows(3) {
+        let sum = window.iter().sum();
+        if let Some(prev) = prev {
+            if prev < sum {
+                increases += 1;
+            }
+        }
+        prev = Some(sum);
+    }
+
+    Ok(increases)
+}

aoc2021/src/lib.rs

@@ -1,3 +1,3 @@
 #![warn(clippy::explicit_iter_loop, clippy::redundant_closure_for_method_calls)]
 
-pub mod day00;
+pub mod day01;

aoc2021/src/main.rs

@@ -2,10 +2,10 @@ use anyhow::Result;
 
 use aoc::DayFunc;
 
-use aoc2021::day00;
+use aoc2021::day01;
 
 fn main() -> Result<()> {
-    let days: &[DayFunc] = &[day00::run];
+    let days: &[DayFunc] = &[day01::run];
 
     aoc::run(days)
 }