src/day4pt2.rs


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pub fn main() {
    let txt = std::fs::read_to_string("./input/day4.txt").unwrap();
    let mut sum: u32 = 0;
    let mut a = vec![1; 256];

    for (idx, line) in txt.lines().enumerate() {
        let mut cnt: u32 = 0;

        let mut br1 = vec![];
        let mut br2 = vec![];

        let sec_pt = line
            .split(": ")
            .collect::<Vec<&str>>()
            .get(1)
            .unwrap()
            .split(" | ")
            .collect::<Vec<&str>>();
        for i in sec_pt.get(0).unwrap().split(r" ") {
            if i == "" {
                continue;
            }
            br1.push(i.parse::<u32>().unwrap());
        }

        for i in sec_pt.get(1).unwrap().split(r" ") {
            if i == "" {
                continue;
            }
            br2.push(i.parse::<u32>().unwrap());
        }

        for i in &br1 {
            for j in &br2 {
                if i == j {
                    cnt += 1;
                }
            }
        }

        for i in 1..cnt + 1 {
            a[idx + i as usize] += a[idx];
        }

        sum += a[idx];
    }

    println!("{}", sum);
}