Can someone please explain why this solution is most voted as Best Practices? it's a concise one-liner but I thought loop-based solution might be more appropriate.

This code generates an extra List object and an extra job for the garbage collector.

String that I got >@=<UEWNWL48@=>P6EDB80=\21PW2H\D:B^D657<62OHPV\4KZ43[NCE[Q;UGOOS6TGFA^8F<2FCJL@:C9<>@I=[

expected:<[>@=<U3WNW148@=>P63D880=\21PW2#\D:8^D657<620#PV\4K243[N(3[Q;U600$676F@^8F<2F(J1@:(9<>@!=[]> but was:<[U3WNW1P3D8PW#D8D0#PVK2N(3QU600$76F@FF(J1(!]>
There is no symbols in alphabet like "=>@"

Did you convert the strings to upper case?

{
    "A": "@",
    "B": "8",
    "C": "(",
    "D": "D",
    "E": "3",
    "F": "F",
    "G": "6",
    "H": "#",
    "I": "!",
    "J": "J",
    "K": "K",
    "L": "1",
    "M": "M",
    "N": "N",
    "O": "0",
    "P": "P",
    "Q": "Q",
    "R": "R",
    "S": "$",
    "T": "7",
    "U": "U",
    "V": "V",
    "W": "W",
    "X": "X",
    "Y": "Y",
    "Z": "2"
}

That's weird. I just solved it using the map from the description.

Sorry, i have forgot. I have problem with random tests Java.

I suspect you are referring to the Java translation.

To which language are you refering? Not Python, I presume.

I have passed tests, but I can't pass random tests, because random tests contain symbols that not in your alphabet. Please update alphabet.

In Java you need to throw new IllegalArgumentException if radius <=0 .

Good luck :)

Not a suggestion.

Do not account the minus (-).
Good luck.

Nice :)