#[path = "../lib.rs"]
mod lib;

fn get_start_values(numbers: &Vec<i64>) -> Vec<i64> {
    let mut tmp = numbers.clone();
    let mut start_values = vec![];

    while tmp.iter().any(|x| *x != 0) {
        for i in (1..tmp.len()).rev() {
            tmp[i] -= tmp[i - 1];
        }
        start_values.push(tmp.remove(0));
    }

    return start_values;
}

fn get_value(v: &Vec<i64>, i: i64) -> i64 {
    let mut sum = 0;
    let mut base = 1;
    for (k, x) in v.iter().enumerate() {
        if k > 0 {
            base = base * (i - (k as i64) + 1) / (k as i64);
        }
        sum += x * base;
    }
    return sum;
}

fn main() {
    let mut sum1 = 0;
    let mut sum2 = 0;

    for line in lib::iter_input() {
        let numbers = line
            .split_whitespace()
            .map(|s| s.parse().unwrap())
            .collect();
        let v = get_start_values(&numbers);
        sum1 += get_value(&v, numbers.len() as i64);
        sum2 += get_value(&v, -1);
    }

    println!("part1: {}", sum1);
    println!("part2: {}", sum2);
}