Day 25: Code Chronicle
Megathread guidelines
- Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
- You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL
FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
Rust
Nice ending for this year. Lock and key arrays are just added together and all elements must be <= 5. Merry Christmas!
Solution
fn flatten_block(block: Vec<Vec<bool>>) -> [u8; 5] { let mut flat = [0; 5]; for row in &block[1..=5] { for x in 0..5 { if row[x] { flat[x] += 1; } } } flat } fn parse(input: &str) -> (Vec<[u8; 5]>, Vec<[u8; 5]>) { let mut locks = Vec::new(); let mut keys = Vec::new(); for block_s in input.split("\n\n") { let block: Vec<Vec<bool>> = block_s .lines() .map(|l| l.bytes().map(|b| b == b'#').collect::<Vec<bool>>()) .collect(); assert_eq!(block.len(), 7); // Lock if block[0].iter().all(|e| *e) { locks.push(flatten_block(block)); } else { keys.push(flatten_block(block)); } } (locks, keys) } fn part1(input: String) { let (locks, keys) = parse(&input); let mut count = 0u32; for l in locks { for k in &keys { if l.iter().zip(k).map(|(li, ki)| li + ki).all(|sum| sum <= 5) { count += 1; } } } println!("{count}"); } fn part2(_input: String) { println!("⭐"); } util::aoc_main!();
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