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Improve perf of day 4

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Tyler Hallada
2025-12-05 01:25:14 -05:00
parent 8f4bc5b802
commit 9de4d77a63
2 changed files with 22 additions and 18 deletions
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2
README.md
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@@ -35,4 +35,4 @@ Timings are given as: [lower-bound **best-estimate** upper-bound]
| 01 | [101.34 µs **101.95 µs** 102.61 µs] | [105.90 µs **106.40 µs** 106.95 µs] | | 01 | [101.34 µs **101.95 µs** 102.61 µs] | [105.90 µs **106.40 µs** 106.95 µs] |
| 02 | [2.0990 ms **2.1113 ms** 2.1236 ms] | [2.0954 ms **2.1055 ms** 2.1157 ms] | | 02 | [2.0990 ms **2.1113 ms** 2.1236 ms] | [2.0954 ms **2.1055 ms** 2.1157 ms] |
| 03 | [38.717 µs **39.002 µs** 39.311 µs] | [175.35 µs **176.59 µs** 177.92 µs] | | 03 | [38.717 µs **39.002 µs** 39.311 µs] | [175.35 µs **176.59 µs** 177.92 µs] |
| 04 | [233.55 µs **234.88 µs** 236.20 µs] | [3.1026 ms **3.1174 ms** 3.1326 ms] | | 04 | [147.02 µs **147.75 µs** 148.53 µs] | [1.5579 ms **1.5737 ms** 1.5900 ms] |

38
src/day04/mod.rs
View File

@@ -8,6 +8,17 @@ use tracing::{debug, instrument};
pub const INPUT: &str = include_str!("input/input.txt"); pub const INPUT: &str = include_str!("input/input.txt");
const ADJACENT_DELTAS: [(isize, isize); 8] = [
(-1, -1),
(-1, 0),
(-1, 1),
(0, -1),
(0, 1),
(1, -1),
(1, 0),
(1, 1),
];
#[derive(Debug, Clone, Copy, PartialEq, Eq)] #[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum Cell { enum Cell {
Empty, Empty,
@@ -77,14 +88,6 @@ impl<const R: usize, const C: usize> Display for Grid<R, C> {
} }
impl<const R: usize, const C: usize> Grid<R, C> { impl<const R: usize, const C: usize> Grid<R, C> {
fn get_cell(&self, row: isize, col: isize) -> Option<Cell> {
if row >= 0 && col >= 0 && (row as usize) < R && (col as usize) < C {
Some(self.cells[row as usize][col as usize])
} else {
None
}
}
fn count_accessible_papers(&mut self, replace_with: Cell) -> usize { fn count_accessible_papers(&mut self, replace_with: Cell) -> usize {
let mut count = 0; let mut count = 0;
for row in 0..R { for row in 0..R {
@@ -93,15 +96,16 @@ impl<const R: usize, const C: usize> Grid<R, C> {
continue; continue;
} }
let mut adjacent_papers = 0; let mut adjacent_papers = 0;
for dr in -1..=1 { for &(dr, dc) in &ADJACENT_DELTAS {
for dc in -1..=1 { let adj_row = row as isize + dr;
if dr == 0 && dc == 0 { let adj_col = col as isize + dc;
continue; if adj_row >= 0
} && adj_col >= 0
let adjacent = self && (adj_row as usize) < R
.get_cell(row as isize + dr, col as isize + dc) && (adj_col as usize) < C
.unwrap_or(Cell::Empty); {
if adjacent == Cell::Paper || adjacent == Cell::AccessiblePaper { let adjacent = self.cells[adj_row as usize][adj_col as usize];
if matches!(adjacent, Cell::Paper | Cell::AccessiblePaper) {
adjacent_papers += 1; adjacent_papers += 1;
} }
} }