Advent of code day 1

lib.rs

<!-- Advent of code day 1 -->

pub fn calculate_part_1(input: &str) -> i32 {
    let mut lines = input.lines();
    let first: i32 = lines.next().unwrap().parse().unwrap();

    let mut larger = 0;
    let mut last_line = first;

    for line in lines {
        let line = line.parse::<i32>().unwrap();

        if last_line < line {
            larger += 1;
        }

        last_line = line;
    }

    larger
}
                           
pub fn calculate_part_2(input: &str) -> i32 {
    let mut lines: Lines = input.lines();

    let mut larger = 0;

    // Build two iterators with differing offsets
    let offset_one = lines.clone().skip(1);
    let offset_two = lines.clone().skip(2);

    // Create one iterator that gives us three results at once. Could've used itertools here.
    let mut triplet_iterator = lines.zip(offset_one).zip(offset_two);

    let triplet = triplet_iterator.next().unwrap();

    // Generate initial value
    let (first, second, third): (i32, i32, i32) = (triplet.0.0.parse().unwrap(), triplet.0.1.parse().unwrap(), triplet.1.parse().unwrap());
    let mut last_triplet_total = first + second + third;


    // For each triplet, calculate the total and see if larger
    for triplet in triplet_iterator {
        let (first, second, third): (i32, i32, i32) = (triplet.0.0.parse().unwrap(), triplet.0.1.parse().unwrap(), triplet.1.parse().unwrap());


        println!("({}, {}, {})", first, second, third);

        let total = first + second + third;

        if last_triplet_total < total {
            larger += 1;
        }

        last_triplet_total = total;
    }

    larger
}