1 files changed, 21 insertions, 0 deletions

diff --git a/day1/src/main.rs b/day1/src/main.rs
new file mode 100644
index 0000000..dd64a15
--- /dev/null
+++ b/day1/src/main.rs
@@ -0,0 +1,21 @@
+use std::fs;
+
+/* AOC21 Day 1: https://adventofcode.com/2021/day/1 */
+fn main() {
+    let input = "resources/input.txt";
+    let content = fs::read_to_string(input).expect("Unable to read input file.");
+    let sweep: Vec<u32> = content.lines().map(|l| l.parse::<u32>().expect("Malformed input")).collect();
+    ex1(&sweep);
+    ex2(&sweep);
+}
+
+fn ex1(sweep: &[u32]) {
+    let incs = sweep.windows(2).fold(0, |a, w| if w[0] < w[1] { a+1 } else { a });
+    println!("Ex1: depth increases {} times.", incs);
+}
+
+fn ex2(sweep: &[u32]) {
+    let avg3: Vec<u32> = sweep.windows(3).map(|w| w[0] + w[1] + w[2]).collect();
+    let incs = avg3.windows(2).fold(0, |a, w| if w[0] < w[1] { a+1 } else { a });
+    println!("Ex2: depth increases {} times.", incs);
+}