Solutions for 2022, as well as 2015-2018 and 2019 up to day 11

2015/day10-elves_look_elves_say/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "day10-elves_look_elves_say"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2015/day10-elves_look_elves_say/src/lib.rs

@@ -0,0 +1,50 @@
+pub fn run(input: &str, count: u8) -> String {
+    let mut look = String::from(input);
+    for _ in 0..count {
+        look = look_and_say(&look);
+    }
+
+    look
+}
+
+fn look_and_say(number: &str) -> String {
+    let mut say = String::new();
+    let mut last_digit = ' ';
+    let mut count = 0;
+
+    for digit in number.chars() {
+        if digit == last_digit {
+            count += 1;
+        } else {
+            say += &(count.to_string() + &last_digit.to_string());
+            count = 1;
+            last_digit = digit;
+        }
+    }
+    say += &(count.to_string() + &last_digit.to_string());
+    say[2..].to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    /*use std::fs::read_to_string;
+
+    fn read_file(name: &str) -> String {
+        read_to_string(name).expect(&format!("Unable to read file: {}", name)[..])
+    }*/
+
+    #[test]
+    fn test_sample() {
+        let sample_input = "1";
+        assert_eq!(run(sample_input, 5), "312211".to_string());
+    }
+
+    #[test]
+    fn test_challenge() {
+        let challenge_input = "1113122113";
+        let after_40 = run(challenge_input, 40);
+        assert_eq!(after_40.len(), 360154);
+        assert_eq!(run(&after_40, 10).len(), 5103798);
+    }
+}