adv01-1.rs

fn digits_to_vec(digits: String) -> Vec<u32> {
    let mut result = Vec::new();
    for c in digits.chars() {
        match c.to_digit(10) {
            Some(v) => result.push(v),
            None => {}
        }
    }
    return result;
}

fn main() {
    let mut digits_string = String::new();
    std::io::stdin().read_line(&mut digits_string).expect("wtf?");
    let digits = digits_to_vec(digits_string);
    let mut sum = 0;
    let mut last = digits[digits.len() - 1];
    for digit in digits {
        if digit == last {
            sum += digit;
        }
        last = digit;
    }
    println!("{}", sum);
}