Day 25: Code Chronicle
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2 points
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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