@manwar Again, #RakuLang offers some #OneLiner solutions to the challenge:

Count Prefixes: ```
@array.map({$str.starts-with($_)}).sum
```

Valid Times: ```
([X~] .comb.map({ /\?/ ?? (0..9) !! $_})).grep(/^$<h>=[\d\d]\:$<m>=[\d\d]$ <?{ $<h> < 24 && $<m> < 60 }>/).elems
```