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#![feature(iter_array_chunks)]
use std::io;
fn main() -> io::Result<()> {
let disk_map = io::stdin()
.lines()
.flatten()
.next()
.unwrap()
.chars()
.map(|c| c as u8 - b'0')
.collect();
let silver: usize = silver(&disk_map);
let gold: usize = gold(&disk_map);
println!("silver: {silver}");
println!("gold: {gold}");
return Ok(());
}
fn silver(input: &Vec<u8>) -> usize {
let mut blocks = input
.iter()
.chain([0, 0].iter()) // lol
.array_chunks()
.enumerate()
.map(|(n, [&f, &s])| [[Some(n)].repeat(f as usize), [None].repeat(s as usize)])
.flatten()
.flatten()
.collect::<Vec<_>>();
let mut l = 0;
let mut r = blocks.len() - 1;
loop {
while blocks[r].is_none() {
r -= 1;
}
while blocks[l].is_some() {
l += 1;
}
if l >= r {
break;
}
let [left, right] = blocks.get_disjoint_mut([l, r]).unwrap();
left.replace(right.take().unwrap());
}
blocks
.iter()
.enumerate()
.map(|(n, id)| n * id.unwrap_or_default())
.sum()
}
fn gold(input: &Vec<u8>) -> usize {
let mut blocks = input
.iter()
.chain([0, 0].iter()) // lol
.array_chunks()
.enumerate()
.map(|(n, [&f, &s])| [(Some(n), f as usize), (None, s as usize)])
.flatten()
.collect::<Vec<_>>();
let mut r = blocks.len();
while r > 0 {
r -= 1;
let (Some(_), f) = blocks[r] else {
continue;
};
// find some empty space and maybe split
let Some(l) = blocks.iter().position(|b| b.0.is_none() && b.1 >= f) else {
continue;
};
if l > r {
continue;
};
let (_, s) = &mut blocks[l];
let diff = *s - f;
if diff > 0 {
*s = f;
blocks.insert(l + 1, (None, diff));
r += 1;
}
blocks.swap(l, r);
}
blocks
.iter()
.map(|&(id, n)| [id].repeat(n))
.flatten()
.enumerate()
.map(|(n, id)| n * id.unwrap_or_default())
.sum()
}
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