Conditions?

i don't even know you can use awk like that lmao. such a one liner <3. using tail is excellent, since you dont have to reverse the sorting

the conditions, man :D

always love the one-liner solution. rly cool stuff

it's because the real test may use tons of cases, and the server can't actually calculate them up in a limited time. mainly caused by the algorithm that you're using.
i got that error earlier too (different kata). i used for loop then have multiple nested-if on the block. so i changed the code structure somehow to use more simpler approach. and finally it can test all of the cases. rly cool stuff

you can simply use range in valid, like valid="a-mA-M", even it can support upper-casing. cool stuff

is the vertical line act like OR operators ?