diff options
Diffstat (limited to 'src/bin/2022/day20.rs')
-rw-r--r-- | src/bin/2022/day20.rs | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/src/bin/2022/day20.rs b/src/bin/2022/day20.rs new file mode 100644 index 0000000..654ea60 --- /dev/null +++ b/src/bin/2022/day20.rs @@ -0,0 +1,74 @@ +#![allow(dead_code)] +#![allow(unused_variables)] + +use advent_of_code::prelude::*; + +#[derive(Default)] +pub struct WrappingQueue { + queue: Vec<(usize, isize)>, +} + +impl std::fmt::Debug for WrappingQueue { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.debug_list() + .entries(self.queue.iter().copied().map(|v| v.1)) + .finish() + } +} + +impl WrappingQueue { + fn mix(&mut self, idx: usize) { + let val = self.queue.remove(idx); + let new_idx: usize = ((idx as isize + val.1) + .rem_euclid(self.queue.len() as isize)) + .try_into() + .unwrap(); + self.queue.insert(new_idx, val); + } +} + +pub fn parse(fh: File) -> Result<WrappingQueue> { + Ok(WrappingQueue { + queue: parse::lines(fh).enumerate().collect(), + }) +} + +pub fn part1(mut q: WrappingQueue) -> Result<isize> { + for i in 0..q.queue.len() { + let idx = q.queue.iter().position(|(idx, _)| *idx == i).unwrap(); + q.mix(idx); + } + let zero_idx = q.queue.iter().position(|(_, val)| *val == 0).unwrap(); + Ok(q.queue[(zero_idx + 1000) % q.queue.len()].1 + + q.queue[(zero_idx + 2000) % q.queue.len()].1 + + q.queue[(zero_idx + 3000) % q.queue.len()].1) +} + +pub fn part2(q: WrappingQueue) -> Result<isize> { + let key = 811589153; + let mut q = WrappingQueue { + queue: q.queue.into_iter().map(|(i, v)| (i, key * v)).collect(), + }; + for _ in 0..10 { + for i in 0..q.queue.len() { + let idx = q.queue.iter().position(|(idx, _)| *idx == i).unwrap(); + q.mix(idx); + } + } + let zero_idx = q.queue.iter().position(|(_, val)| *val == 0).unwrap(); + Ok(q.queue[(zero_idx + 1000) % q.queue.len()].1 + + q.queue[(zero_idx + 2000) % q.queue.len()].1 + + q.queue[(zero_idx + 3000) % q.queue.len()].1) +} + +#[test] +fn test() { + assert_eq!( + part1(parse(parse::data(2022, 20).unwrap()).unwrap()).unwrap(), + 17490 + ); + assert_eq!( + part2(parse(parse::data(2022, 20).unwrap()).unwrap()).unwrap(), + 1632917375836 + ); +} |