All problems were prepared by me and magnus.hegdahl. Thanks to BucketPotato and Monogon for valuable feedback and testing. Special thanks to MikeMirzayanov for the comingh up with the idea and preparing the unique checker for 1663H - Cross-Language Program. I hope you enjoyed the contest.

Example Python code written by Agnimandur is provided for each problem.

1663A - Who Tested?

print("bucketpotato")

1663B - Mike's Sequence

1663C - Pōja Verdon

pōja means their and verdon means sum (or amount based on context) in High Valyrian (you can easily translate this on Duolingo).

In a nutshell: Print the sum of the array.

1663D - Is it rated - 3

The problem is asking whether the Atcoder contest (ABC,ARC,AGC) is rated for a rating $$$X$$$. (Note that the judge ignores Atcoder heuristic contests for simplicity).

• ABC's are rated for $$$[0,1999]$$$
• ARC's are rated for $$$[0,2799]$$$
• AGC's are rated for $$$[1200,\infty]$$$

1663E - Are You Safe?

The problem is just a word search (horizontal, vertical, diagonal) for theseus. You should only go in the forward direction when you search for a word.

There are also some red herring words out there.

1663F - In Every Generation...

Perhaps you notice the lengths of the words buffy, the, vampire, slayer are unique integers in the set {3,5,6,7}.

Given the string $$$s$$$, simply "add" that string with the target word of the same length.

Here's how adding two letters work:

1. Convert both letters to numbers in $$$[0,25]$$$.
2. Add the two numbers up modulo 26.
3. Convert the number back into a letter.

You can verify your addition algorithm is correct by checking whether "tourist" + "vampire" = "ooggqjx" (as provided in the sample).

Finally, if the length of $$$s$$$ is $$$4$$$, the answer is "none", because there is no word of length 4 in Buffy the Vampire Slayer.

1663G - Six Characters

The six characters is a pun: the input is a string of length 6 like "abcdef", but the output is a string \textit{consisting} of only 6 characters: [ ] ( ) ! +.

Brief research will demonstrate a mapping from each english letter to a JSFuck string. Two letters can be concatenated with "+".Note that the optimal mapping will make your solution file approximately 12KB in size, well within the 64KB requirement of Codeforces.

However, the mapping from each letter to javascript is not unique! However, the legend mentions that Aenar needs to go to the string's "home". JSFuck's home website is here, which is where the jury's mapping is created from.

1663H - Cross-Language Program

// \
begin end.
int main() {}