2020: day14: refacto to prepare part 2

This commit is contained in:
Antoine Martin 2020-12-14 11:41:41 +01:00
parent 514a93213c
commit b0c1b83c19

View file

@ -22,22 +22,25 @@ fn part1(input: &str) -> aoc::Result<u64> {
}
#[derive(Debug, Clone, Copy)]
enum MaskType {
And,
Or,
enum Mask {
Floating,
One,
Zero,
}
#[derive(Debug, Clone)]
struct BitMask {
masks: Vec<(MaskType, u64)>,
masks: Vec<Mask>,
}
impl BitMask {
fn apply(&self, mut n: u64) -> u64 {
for (mask_type, mask) in &self.masks {
match mask_type {
MaskType::And => n &= mask,
MaskType::Or => n |= mask,
/// function used for part 1: 'X' bits just don't do anything
fn apply_no_floating(&self, mut n: u64) -> u64 {
for (offset, mask) in self.masks.iter().enumerate() {
match mask {
Mask::Floating => {}
Mask::One => n |= 1 << offset,
Mask::Zero => n &= !(1 << offset),
}
}
@ -52,18 +55,14 @@ impl std::str::FromStr for BitMask {
let masks = s
.chars()
.rev()
.enumerate()
.filter_map(|(idx, c)| match c {
'1' => {
let m = 1 << idx;
Some(Ok((MaskType::Or, m)))
.map(|c| {
// idx will never be higher than 36 so this is fine
match c {
'1' => Ok(Mask::One),
'0' => Ok(Mask::Zero),
'X' => Ok(Mask::Floating),
_ => Err(err!("unknown character in mask: `{}`", c)),
}
'0' => {
let m = !(1 << idx);
Some(Ok((MaskType::And, m)))
}
'X' => None,
_ => Some(Err(err!("unknown character in mask: `{}`", c))),
})
.collect::<aoc::Result<_>>()?;
@ -134,7 +133,8 @@ impl Program {
Instruction::MemWrite { offset, value } => match &self.current_mask {
Some(bitmask) => {
self.memory.insert(*offset, bitmask.apply(*value));
self.memory
.insert(*offset, bitmask.apply_no_floating(*value));
}
None => {
return Err(err!("tried to execute MemWrite but mask isn't initialized"))