Update day12.rs

crates/core/src/year2023/day12.rs

@@ -76,9 +76,7 @@ fn count_alternatives(damaged: u128, unknown: u128, groups: &[u8]) -> u64 {
     // with bits set at positions up until the first damaged position
     // - note that we inserted an unset bit above.
     let mut alternatives = [0; 128];
-    for i in 0..damaged.trailing_zeros() {
-        alternatives[i as usize] = 1;
-    }
+    (&mut alternatives[0..(damaged.trailing_zeroes() as usize)]).fill(1);
 
     // For each group that is necessary, go over all the positions
     // and carry over possibilities from the previous run at positions