2015: day04: part 2

This commit is contained in:
Antoine Martin 2019-12-03 15:40:50 +01:00
parent 33b89f6269
commit a5911369e5

View file

@ -7,6 +7,7 @@ const INPUT: &str = include_str!("../input/day04.txt");
pub fn run() -> Result<()> {
println!("part 1: {}", part1(INPUT)?);
println!("part 2: {}", part2(INPUT)?);
Ok(())
}
@ -31,6 +32,26 @@ fn part1(input: &str) -> Result<u64> {
Err(err!("couldn't find a suitable number"))
}
fn part2(input: &str) -> Result<u64> {
let input = input.trim_end();
let mut content = String::from(input);
let mut hasher = Md5::new();
for i in 0.. {
content.truncate(input.len());
content.extend(i.to_string().chars());
hasher.input(&content);
let res = hasher.result_reset();
if &res[..3] == &[0, 0, 0] {
return Ok(i);
}
}
Err(err!("couldn't find a suitable number"))
}
#[cfg(test)]
mod tests {
use super::*;
@ -47,4 +68,10 @@ mod tests {
fn part1_real() {
assert_eq!(part1(INPUT).unwrap(), 282749);
}
#[test]
#[ignore] // takes too long!
fn part2_real() {
assert_eq!(part2(INPUT).unwrap(), 9962624);
}
}