Day22 - part 1

diff --git a/src/day22.rs b/src/day22.rs
new file mode 100644 (file)
index 0000000..c30a8d0
--- /dev/null
+++ b/src/day22.rs
@@ -0,0 +1,80 @@
+use std::error::Error;
+use std::path::Path;
+
+fn mix(value: u64, secret: u64) -> u64 {
+    value ^ secret
+}
+
+fn prune(value: u64) -> u64 {
+    value % 16777216
+}
+
+fn new_secret(secret: u64, steps: usize) -> u64 {
+    let mut s = secret;
+    for i in 0..steps {
+        s = prune(mix(s * 64, s));
+        s = prune(mix(s / 32, s));
+        s = prune(mix(s * 2048, s));
+    }
+    s
+}
+
+fn run_part1(input: &str) -> Result<u64, Box<dyn Error>> {
+    println!("Running {} - part 1", get_day());
+
+    let res: u64 = input.lines()
+        .map(|l| l.parse::<u64>().unwrap())
+        .map(|secret| new_secret(secret, 2000))
+        .sum();
+
+    Ok(res)
+}
+
+fn run_part2(input: &str) -> Result<u64, Box<dyn Error>> {
+    println!("Running {} - part 2", get_day());
+
+    Ok(0)
+}
+
+pub fn run(input: &str) -> Result<(), Box<dyn Error>> {
+    let res = run_part1(input)?;
+    println!("{res}");
+
+    let res = run_part2(input)?;
+    println!("{res}");
+
+    Ok(())
+}
+
+fn get_day() -> String {
+    let filename = file!();
+    Path::new(filename).file_stem().unwrap().to_str().unwrap().to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    static TEXT_INPUT: &str = "\
+";
+
+    #[test]
+    fn test_part1() {
+        let secret_123_steps = vec![
+            15887950, 16495136, 527345, 704524, 1553684,
+            12683156, 11100544, 12249484, 7753432, 5908254,
+        ];
+        for step in 0..secret_123_steps.len() {
+            assert_eq!(new_secret(123, step + 1), secret_123_steps[step]);
+        }
+        assert_eq!(new_secret(1, 2000), 8685429);
+        assert_eq!(new_secret(10, 2000), 4700978);
+        assert_eq!(new_secret(100, 2000), 15273692);
+        assert_eq!(new_secret(2024, 2000), 8667524);
+    }
+
+    #[test]
+    fn test_part2() {
+        assert_eq!(0, run_part2(TEXT_INPUT).unwrap());
+    }
+}

diff --git a/src/main.rs b/src/main.rs
index c5ea0ce2e2a919ecb16dbaac457a404f7a752a11..65c8fd2022975ac16c73c2f34bdb6a06737e7a5c 100644 (file)
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,6 +24,7 @@ pub mod day17;
 pub mod day18;
 pub mod day19;
 pub mod day20;
+pub mod day22;
 
 fn main() {
     let args: Vec<String> = env::args().collect();
@@ -66,6 +67,7 @@ fn run(day: &str, input_file: &str) -> Result<(), Box<dyn Error>> {
         "day18" => day18::run(&input)?,
         "day19" => day19::run(&input)?,
         "day20" => day20::run(&input)?,
+        "day22" => day22::run(&input)?,
         _ => return Err(format!("unknown or unimplemented day \"{day}\"").into()),
     }
     Ok(())