Improve day06b

Author: timvisee

README.md

@@ -25,7 +25,7 @@ scientifically) in [`bench.rs`](./runner/src/bin/bench.rs) on an
 | [day 3](https://adventofcode.com/2022/day/3) | [` 0.015 ms`](./day03a/src/main.rs) | [` 0.016 ms`](./day03b/src/main.rs) |
 | [day 4](https://adventofcode.com/2022/day/4) | [` 0.040 ms`](./day04a/src/main.rs) | [` 0.039 ms`](./day04b/src/main.rs) |
 | [day 5](https://adventofcode.com/2022/day/5) | [` 0.020 ms`](./day05a/src/main.rs) | [` 0.019 ms`](./day05b/src/main.rs) |
-| [day 6](https://adventofcode.com/2022/day/6) | [` 0.001 ms`](./day06a/src/main.rs) | [` 720 ns`](./day06b/src/main.rs) |
+| [day 6](https://adventofcode.com/2022/day/6) | [` 0.001 ms`](./day06a/src/main.rs) | [` 550 ns`](./day06b/src/main.rs) |
 | [day 7](https://adventofcode.com/2022/day/7) | [` 0.008 ms`](./day07a/src/main.rs) | [` 0.011 ms`](./day07b/src/main.rs) |
 | [day 8](https://adventofcode.com/2022/day/8) | [` 0.045 ms`](./day08a/src/main.rs) | [` 0.177 ms`](./day08b/src/main.rs) |
 | [day 9](https://adventofcode.com/2022/day/9) | [` 0.120 ms`](./day09a/src/main.rs) | [` 0.290 ms`](./day09b/src/main.rs) |

day06b/src/main.rs

@@ -1,19 +1,18 @@
 pub fn main() {
- let d = include_bytes!("../input.txt");
-
- let mut w = 0;
- 'main: loop {
+ let mut i = 0;
+ while let Some(win) = include_bytes!("../input.txt").get(i..i + 14) {
  let mut seen = 0u32;
- for i in (0..=13).rev() {
- let mask = 1 << d[w + i] - b'a';
- if seen & mask == mask {
- w += i + 1;
- continue 'main;
- }
- seen |= mask;
+ if let Some(pos) = win.iter().rposition(|b| {
+ let bit = 1 << (b % 32);
+ let duplicate = seen & bit != 0;
+ seen |= bit;
+ duplicate
+ }) {
+ i += pos + 1;
+ } else {
+ break;
  }
- break;
  }
 
- println!("{}", w + 14);
+ println!("{}", i);
 }