pub fn main() {
    let txt = std::fs::read_to_string("./input/day9.txt").unwrap();
    let mut sum: i64 = 0;

    for line in txt.lines() {
        let mut razlike_all = vec![];
        let mut razlike = vec![];
        let mut brojevi: Vec<i64> = line.split(" ").map(|s| s.parse::<i64>().unwrap()).collect();

        razlike_all.push(brojevi.clone());
        while !brojevi.is_empty() {
            let mut ind: bool = true;
            for i in 0..brojevi.len() {
                if brojevi[i] != 0 {
                    ind = false;
                }
            }
            if ind {
                break;
            }

            for i in 0..brojevi.len() - 1 {
                razlike.push(brojevi[i + 1] - brojevi[i]);
            }
            razlike_all.push(razlike.clone());
            brojevi = razlike.clone();
            razlike.clear();
        }

        let mut sl: i64 = 0;
        for i in razlike_all {
            sl += i[i.len() - 1] as i64;
        }

        sum += sl;
    }

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