AoC2022/06/solver.rs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

use std::fs;
use std::io::{self, Read};

fn solver(bytes: &Vec<u8>, marker_len: u32) -> u32 {
    let mut count = marker_len;
    for view in bytes.windows(marker_len as usize) {
        let mut acc: u32 = 0;
        for elt in view {
            acc |= 1 << (elt - 96);
        }
        if u32::count_ones(acc) >= marker_len {
            break;
        }
        count += 1;
    }
    count
}

fn main() -> io::Result<()> {
    let mut file = fs::File::open("input").unwrap();
    let mut bytes: Vec<u8> = Vec::new();
    file.read_to_end(&mut bytes)?;
    println!("All test passed. {}", solver(&bytes, 4));
    println!("All test passed. {}", solver(&bytes, 14));

    Ok(())
}