79 lines
2.0 KiB
Rust
79 lines
2.0 KiB
Rust
use hashbrown::HashMap;
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use itertools::Itertools;
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use md5::{Digest, Md5};
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pub fn part_one(input: &str) -> Option<String> {
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let key = input.trim().as_bytes();
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let mut hasher = Md5::new();
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let mut count = 0;
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let mut res = String::new();
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for x in 0..std::u64::MAX {
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hasher.update(key);
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hasher.update(x.to_string().as_bytes());
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let output = hasher.finalize_reset();
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if output.starts_with(&[0, 0]) && output[2] <= 0x0F {
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count += 1;
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res.push_str(&format!("{:02x}", output[2])[1..]);
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}
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if count == 8 {
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break;
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}
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}
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Some(res)
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}
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pub fn part_two(input: &str) -> Option<String> {
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let key = input.trim().as_bytes();
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let mut hasher = Md5::new();
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let mut res = HashMap::new();
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for x in 0..std::u64::MAX {
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hasher.update(key);
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hasher.update(x.to_string().as_bytes());
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let output = hasher.finalize_reset();
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if output.starts_with(&[0, 0]) && output[2] <= 0x0F {
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let (p, c) = format!("{:02x}{:02x}", output[2], output[3])[1..3]
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.chars()
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.next_tuple()
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.unwrap();
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if ('0'..='7').contains(&p) && !res.contains_key(&p) {
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res.insert(p, c);
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}
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}
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if res.len() == 8 {
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break;
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}
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}
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Some(
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res.iter()
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.sorted_by(|a, b| a.0.cmp(b.0))
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.map(|(_, v)| v)
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.collect(),
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)
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}
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fn main() {
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let input = &aoc::read_file("inputs", 5);
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aoc::solve!(1, part_one, input);
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aoc::solve!(2, part_two, input);
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_part_one() {
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let input = aoc::read_file("examples", 5);
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assert_eq!(part_one(&input), Some("18f47a30".to_string()));
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}
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#[test]
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fn test_part_two() {
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let input = aoc::read_file("examples", 5);
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assert_eq!(part_two(&input), Some("05ace8e3".to_string()));
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}
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}
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