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| 1 | +use aoc_runner_derive::{aoc, aoc_generator}; |
| 2 | +use memoize::memoize; |
| 3 | + |
| 4 | +#[aoc_generator(day11)] |
| 5 | +pub fn input_generator(input: &str) -> Vec<usize> { |
| 6 | + input.split(" ").map(|s| s.parse().unwrap()).collect() |
| 7 | +} |
| 8 | + |
| 9 | +// pub fn blink_part1(stones: Vec<usize>, counter: usize, limit: usize) -> Vec<usize> { |
| 10 | +// if counter == limit { |
| 11 | +// return stones; |
| 12 | +// } |
| 13 | +// let stones = stones.iter().fold(vec![], |mut acc, stone| { |
| 14 | +// if *stone == 0 { |
| 15 | +// acc.push(1); |
| 16 | +// return acc; |
| 17 | +// } |
| 18 | +// let mut div = *stone; |
| 19 | +// let mut count = 0; |
| 20 | +// while div > 0 { |
| 21 | +// div /= 10; |
| 22 | +// count += 1; |
| 23 | +// } |
| 24 | +// if count % 2 == 0 { |
| 25 | +// acc.push(*stone / 10_usize.pow(count / 2)); |
| 26 | +// acc.push(*stone % 10_usize.pow(count / 2)); |
| 27 | +// return acc; |
| 28 | +// } |
| 29 | +// acc.push(2024 * *stone); |
| 30 | +// acc |
| 31 | +// }); |
| 32 | +// blink_part1(stones, counter + 1, limit) |
| 33 | +// } |
| 34 | + |
| 35 | +// #[aoc(day11, part1)] |
| 36 | +// pub fn part1(input: &[usize]) -> usize { |
| 37 | +// blink_part1(input.to_vec(), 0, 25).len() |
| 38 | +// } |
| 39 | + |
| 40 | +#[memoize] |
| 41 | +pub fn blink(stone: usize, counter: usize, limit: usize) -> usize { |
| 42 | + let mut stack = 0; |
| 43 | + if counter == limit { |
| 44 | + return 1; |
| 45 | + } |
| 46 | + |
| 47 | + if stone == 0 { |
| 48 | + stack += blink(1, counter + 1, limit); |
| 49 | + } else { |
| 50 | + let mut div = stone; |
| 51 | + let mut count = 0; |
| 52 | + while div > 0 { |
| 53 | + div /= 10; |
| 54 | + count += 1; |
| 55 | + } |
| 56 | + if count % 2 == 0 { |
| 57 | + stack += blink(stone / 10_usize.pow(count / 2), counter + 1, limit); |
| 58 | + stack += blink(stone % 10_usize.pow(count / 2), counter + 1, limit); |
| 59 | + } else { |
| 60 | + stack += blink(stone * 2024, counter + 1, limit); |
| 61 | + } |
| 62 | + } |
| 63 | + stack |
| 64 | +} |
| 65 | + |
| 66 | +#[aoc(day11, part1)] |
| 67 | +pub fn part1(input: &[usize]) -> usize { |
| 68 | + let mut lenght = 0; |
| 69 | + for stone in input { |
| 70 | + lenght += blink(*stone, 0, 25); |
| 71 | + } |
| 72 | + lenght |
| 73 | +} |
| 74 | + |
| 75 | +#[aoc(day11, part2)] |
| 76 | +pub fn part2(input: &[usize]) -> usize { |
| 77 | + let mut lenght = 0; |
| 78 | + for stone in input { |
| 79 | + lenght += blink(*stone, 0, 75); |
| 80 | + } |
| 81 | + lenght |
| 82 | +} |
| 83 | + |
| 84 | +#[cfg(test)] |
| 85 | +mod tests { |
| 86 | + use super::*; |
| 87 | + |
| 88 | + const INPUT: &str = "125 17"; |
| 89 | + |
| 90 | + #[test] |
| 91 | + fn test_part1() { |
| 92 | + assert_eq!(55312, part1(&input_generator(INPUT))) |
| 93 | + } |
| 94 | + |
| 95 | + #[test] |
| 96 | + fn test_part2() { |
| 97 | + assert_eq!(55312, part2(&input_generator(INPUT))) |
| 98 | + } |
| 99 | +} |
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