2022 day 20 rust

2022/rust/src/main.rs

@@ -21,5 +21,6 @@ fn main() {
     // solutions::day16::run();
     // solutions::day17::run();
     // solutions::day18::run();
-    solutions::day19::run();
+    // solutions::day19::run();
+    solutions::day20::run();
 }

2022/rust/src/solutions/day20.rs

@@ -0,0 +1,64 @@
+use std::collections::VecDeque;
+use crate::utils;
+
+
+pub fn run() -> () {
+    let data = parse_data(&utils::read_lines(utils::Source::Day(20)));
+
+    println!("Day 20");
+    println!("Part 1: {}", solve1(&data));
+    println!("Part 2: {}", solve2(&data));
+}
+
+
+fn reorder(data: &[(usize, i32)]) -> Vec<i32> {
+    let mut array = data.iter().copied().collect::<VecDeque<_>>();
+
+    for item in data {
+        let index = array.iter().position(|item_ref| item == item_ref).unwrap();
+        array.remove(index);
+        let index = (index as i32 + item.1).rem_euclid(array.len() as i32) as usize;
+        array.insert(index, *item);
+    }
+
+    let zero_offset = array.iter().position(|item_ref| 0 == item_ref.1).unwrap();
+    array.rotate_left(zero_offset);
+    array.into_iter().map(|x| x.1).collect()
+}
+
+fn solve1(data: &[(usize, i32)]) -> i32 {
+    let array = reorder(data);
+    let len = array.len();
+    array[1000 % len] + array[2000 % len] + array[3000 % len]
+}
+
+fn solve2(data: &[(usize, i32)]) -> i32 {
+    reorder(data);
+    2
+}
+
+
+fn parse_data<T: AsRef<str>>(data: &[T]) -> Vec<(usize, i32)> {
+    data.iter()
+        .enumerate()
+        .map(|(index, line)| (index, line.as_ref().parse().unwrap()))
+        .collect()
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    static DATA: &[&str] = &["1", "2", "-3", "3", "-2", "0", "4"];
+
+    #[test]
+    fn part1() {
+        assert_eq!(3, solve1(&parse_data(DATA)));
+    }
+
+    #[test]
+    fn part2() {
+        assert_eq!(2, solve2(&parse_data(DATA)));
+    }
+}

2022/rust/src/solutions/mod.rs

@@ -17,3 +17,4 @@ pub mod day16;
 pub mod day17;
 pub mod day18;
 pub mod day19;
+pub mod day20;