aoc2021-d1

d1.rs

use common::{input, input_to_vec_ints};

fn p1 (xs: &Vec<i32>) -> u32 {
    let mut iter = xs.iter();
    let mut counter = 0_u32;

    let mut last = iter.next();
    for x in iter {
        if last < Some(x) {
            counter += 1;
        }
        last = Some(x)
    }
    counter
}

fn chunkit(xs: &Vec<i32>, window_size: usize) -> Vec<&[i32]> {
    let stop = xs.len() - window_size + 1;
    let iter = xs.iter().enumerate();
    let mut res: Vec<&[i32]> = Vec::new();

    for x in iter {
        if x.0 == stop {
            return res;
        }
        let chunk = &xs[x.0..(x.0 + window_size)];
        res.push(chunk);
    }
    res
}

fn p2(xs: &Vec<i32>) -> u32 {
    let window_size = 3usize;
    let chunks = chunkit(xs, window_size);
    let chunksums = chunks.iter().map(|c| c.iter().sum()).collect::<Vec<i32>>();
    p1(&chunksums)
}

fn main() {
    let raw: String = input();
    let xs = input_to_vec_ints(&raw);
    let part1 = p1(&xs);
    println!("p1 counter {}", part1);

    let part2 = p2(&xs);
    println!("p2 counter {}", part2);
    
}