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optimized day 6 part 2 by replacing arrays with u32

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Ishan Jain 2022-12-06 11:49:22 +05:30
parent 59f7db787d
commit 94289d0c7a
Signed by: ishan
GPG Key ID: 0506DB2A1CC75C27
1 changed files with 7 additions and 16 deletions
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21
src/main.rs
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@ -21,24 +21,15 @@ fn main() {
} }
fn solution<const N: usize>(input: &[u8]) -> usize { fn solution<const N: usize>(input: &[u8]) -> usize {
let mut buffer = [0; 26]; for idx in 0..input.len() - N {
let mut buffer = 0u32;
for &c in input.iter().take(N) { for &c in &input[idx..(idx + N)] {
buffer[(c - b'a') as usize] += 1; buffer |= 1 << (c - b'a') as usize;
} }
if buffer.iter().all(|&c| c == 0 || c == 1) { if buffer.count_ones() as usize == N {
return 0; return idx + N;
}
for i in N..input.len() {
let c = input[i];
buffer[(c - b'a') as usize] += 1;
let last = input[i - N];
buffer[(last - b'a') as usize] -= 1;
if buffer.iter().all(|&c| c == 0 || c == 1) {
return i + 1;
} }
} }