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day11: some cleanup, slight performance

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This commit is contained in:
Keenan Tims 2024-12-11 01:20:33 -08:00
parent 2e239681ce
commit 3ed3165bd1
Signed by: ktims
GPG Key ID: 11230674D69038D4
1 changed files with 22 additions and 41 deletions
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63
11/src/main.rs
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@ -39,8 +39,18 @@ fn main() {
}
#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
struct Stone {
value: u64,
struct Stone(u64);
struct Stones(Vec<Stone>);
impl From<&str> for Stones {
fn from(input: &str) -> Self {
Stones(
input
.split_ascii_whitespace()
.map(|v| Stone(v.parse().unwrap()))
.collect_vec(),
)
}
}
enum BlinkResult {
@ -50,30 +60,16 @@ enum BlinkResult {
impl Stone {
fn blink_once(self) -> BlinkResult {
let n_digits = if self.value == 0 { 1 } else { self.value.ilog10() + 1 };
if self.value == 0 {
BlinkResult::One(Stone { value: 1 })
let n_digits = if self.0 == 0 { 1 } else { self.0.ilog10() + 1 };
if self.0 == 0 {
BlinkResult::One(Stone(1))
} else if n_digits % 2 == 0 {
let parts = (
self.value / 10u64.pow(n_digits / 2),
self.value % 10u64.pow(n_digits / 2),
);
BlinkResult::Two(Stone { value: parts.0 }, Stone { value: parts.1 })
let parts = (self.0 / 10u64.pow(n_digits / 2), self.0 % 10u64.pow(n_digits / 2));
BlinkResult::Two(Stone(parts.0), Stone(parts.1))
} else {
BlinkResult::One(Stone {
value: self.value * 2024,
})
BlinkResult::One(Stone(self.0 * 2024))
}
}
// #[allow(dead_code)]
// fn blink(self, times: usize) -> Vec<Stone> {
// // Used in submitted part 1 solution
// let mut stones = vec![self];
// for _ in 0..times {
// stones = stones.iter().flat_map(|stone| stone.blink_once()).collect();
// }
// stones
// }
}
fn count_blinks(stone: Stone, blink: usize, cache: &mut Vec<HashMap<Stone, u64>>) -> u64 {
@ -96,9 +92,10 @@ fn count_blinks(stone: Stone, blink: usize, cache: &mut Vec<HashMap<Stone, u64>>
result
}
fn blink_stones(stones: &[Stone], blinks: usize) -> u64 {
fn blink_stones(stones: &Stones, blinks: usize) -> u64 {
let mut cache = Vec::from_iter(repeat(HashMap::new()).take(blinks));
stones
.0
.iter()
.map(|stone| count_blinks(*stone, blinks - 1, &mut cache))
.sum()
@ -107,29 +104,13 @@ fn blink_stones(stones: &[Stone], blinks: usize) -> u64 {
// PROBLEM 1 solution
fn problem1<T: BufRead>(mut input: Lines<T>) -> u64 {
let stones = input
.next()
.unwrap()
.unwrap()
.split_ascii_whitespace()
.map(|v| Stone {
value: v.parse().unwrap(),
})
.collect_vec();
let stones = input.next().unwrap().unwrap().as_str().into();
blink_stones(&stones, 25)
}
// PROBLEM 2 solution
fn problem2<T: BufRead>(mut input: Lines<T>) -> u64 {
let stones = input
.next()
.unwrap()
.unwrap()
.split_ascii_whitespace()
.map(|v| Stone {
value: v.parse().unwrap(),
})
.collect_vec();
let stones = input.next().unwrap().unwrap().as_str().into();
blink_stones(&stones, 75)
}