codspeed-aoc -


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#![allow(
    confusable_idents,
    uncommon_codepoints,
    non_upper_case_globals,
    internal_features,
    mixed_script_confusables,
    incomplete_features
)]
#![feature(
    slice_swap_unchecked,
    iter_repeat_n,
    generic_const_exprs,
    iter_array_chunks,
    get_many_mut,
    maybe_uninit_uninit_array,
    iter_collect_into,
    let_chains,
    anonymous_lifetime_in_impl_trait,
    vec_into_raw_parts,
    array_windows,
    slice_take,
    test,
    slice_as_chunks,
    array_chunks,
    slice_split_once,
    core_intrinsics,
    portable_simd,
    hint_assert_unchecked
)]
mod util;
pub mod day9 {
    use super::util::prelude::*;

    pub fn part2(i: &str) -> impl Display {
        let i = i.as_bytes().trim_ascii_end();
        let mut files = Vec::with_capacity(10000);
        let mut free = Vec::with_capacity(10000);
        let mut j = 0;
        i.iter().ι::<usize>().for_each(|(x, i)| {
            let n = *x - b'0';
            if i % 2 == 1 {
                free.push((n, j));
            } else {
                files.push((n, j));
            }
            j += n as u32;
        });

        for (size, fat) in files.iter_mut().rev() {
            let Some((si, &(space, at))) = free
                .iter()
                .enumerate()
                .take_while(|(_, &(_, j))| j <= *fat)
                .find(|(_, &(s, _))| s >= *size)
            else {
                continue;
            };
            free[si as usize] = (space - *size, at + *size as u32);
            *fat = at;
        }
        files
            .into_iter()
            .ι::<u64>()
            .map(|((size, at), n)| ((size as u64, at as u64), n as u64))
            .map(|((size, at), n)| n * (at * size + (size * (size - 1)) / 2))
            .sum::<u64>()
    }

    #[no_mangle]
    pub fn part1(i: &str) -> impl Display {
        let i = i.as_bytes().trim_ascii_end();
        const SPACE: u16 = u16::MAX;
        let map = i
            .iter()
            .ι::<u16>()
            .flat_map(|(x, i)| {
                let times = (*x - b'0') as usize;
                std::iter::repeat_n(if i % 2 == 1 { SPACE } else { i / 2 }, times)
            })
            .collect::<Vec<_>>();
        let (map, len, _) = map.into_raw_parts();
        let eight_bit = unsafe { std::slice::from_raw_parts(map as *const u8, len * 2) };
        let mut emptys = memchr::memmem::find_iter(eight_bit, &[0xff; 2]).map(|x| x / 2);
        for i in (0..len).rev() {
            if unsafe { *map.add(i) == SPACE } {
                continue;
            }
            let empty = emptys.Δ();
            if empty > i {
                break;
            }
            unsafe { map.add(empty).swap(map.add(i)) };
        }
        unsafe {
            std::slice::from_raw_parts(map, memchr::memmem::find(eight_bit, &[0xff; 2]).ψ() / 2)
        }
        .iter()
        .copied()
        .ι::<usize>()
        .map(|(id, i)| id as usize * i)
        .sum::<usize>()
        // 0
    }
}