Add day06, 2022

2 files changed, 59 insertions, 0 deletions

diff --git a/2022/rust/day06/Cargo.toml b/2022/rust/day06/Cargo.toml
new file mode 100644
index 0000000..cd279fb
--- /dev/null
+++ b/2022/rust/day06/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "day06"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+aoc = { path = "../../../common/rust/aoc" }
+anyhow = "1.0"
diff --git a/2022/rust/day06/src/main.rs b/2022/rust/day06/src/main.rs
new file mode 100644
index 0000000..d7bae65
--- /dev/null
+++ b/2022/rust/day06/src/main.rs
@@ -0,0 +1,51 @@
+use {
+    anyhow::{
+        anyhow,
+        Context,
+        Result,
+    },
+    std::{
+        env::args,
+        fs::read_to_string,
+        path::Path,
+    },
+};
+
+fn read_input<T: AsRef<Path>>(filename: T) -> Result<String> {
+    read_to_string(filename).context("Could not read {filename}")
+}
+
+fn find_sequence(input: &str, len: usize) -> Option<usize> {
+    input.as_bytes().windows(len).enumerate().find_map(|(pos, win)| {
+        for i in 0..len {
+            if win[(i + 1)..].contains(&win[i]) {
+                return None
+            }
+        }
+        Some(pos + len)
+    })
+}
+
+fn part1(input: &str) -> Result<usize> {
+    find_sequence(input, 4).ok_or_else(|| anyhow!("No match found"))
+}
+
+fn part2(input: &str) -> Result<usize> {
+    find_sequence(input, 14).ok_or_else(|| anyhow!("No match found"))
+}
+
+fn main() -> Result<()> {
+    let ( do_part_1, do_part_2 ) = aoc::do_parts();
+
+    let filename = args().nth(1).ok_or_else(|| anyhow!("Missing input filename"))?;
+    let input = read_input(filename).context("Could not read input")?;
+    if do_part_1 {
+        let solution = part1(&input).context("No solution for part 1")?;
+        println!("Part1, solution found to be: {}", solution);
+    }
+    if do_part_2 {
+        let solution = part2(&input).context("No solution for part 2")?;
+        println!("Part2, solution found to be: {}", solution);
+    }
+    Ok(())
+}