use aoc_runner_derive::{aoc, aoc_generator};

type Data = Vec<i64>;

#[aoc_generator(day07)]
pub fn input_generator(input: &str) -> Data {
    let mut input: Vec<_> = input.split(',').map(|v| v.parse().unwrap()).collect();
    input.sort_unstable();
    input
}

#[aoc(day07, part1)] // 336040
pub fn solve_part1(input: &Data) -> i64 {
    let start = *input.first().unwrap();
    let end = *input.last().unwrap();
    (start..=end).map(|n| {
        input.iter().map(|v| {
            (v-n).abs()
        }).sum()
    }).min().unwrap()
}

#[aoc(day07, part2)] // 94813675
pub fn solve_part2(input: &Data) -> i64 {
    let start = *input.first().unwrap();
    let end = *input.last().unwrap();
    (start..=end).map(|n| {
        input.iter().map(|v| {
            let diff=(v-n).abs();
            (diff*(diff+1))>>1 // Gauss
        }).sum()
    }).min().unwrap()
}