### Agnimandur's blog

By Agnimandur, history, 2 years ago,

All problems were created and prepared by me and magnus.hegdahl. Thanks to BucketPotato, Monogon, and Priyam2k for valuable feedback and testing. Special thanks to MikeMirzayanov for coming up with the idea and preparing the unique checker for 1663H - Cross-Language Program. I hope you enjoyed the contest, and found it to be an interesting series of puzzles.

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

### 1663A - Who Tested?

Clue 1
Clue 2
Solution
Solution Code (Python)

### 1663B - Mike's Sequence

Clue 1
Clue 2
Clue 3
Solution
Solution Code (Python)

### 1663C - Pōja Verdon

Clue 1
Clue 2
Solution
Solution Code (Python)

### 1663D - Is it rated - 3

Clue 1
Clue 2
Solution
Solution Code (Python)

### 1663E - Are You Safe?

Clue 1
Clue 2
Solution
Bonus Clues (for other problems)
Solution Code (C++)

### 1663F - In Every Generation...

Clue 1
Clue 2
Clue 3
Solution
Solution Code (Python)

### 1663G - Six Characters

Clue 1
Clue 2
Clue 3
Solution
Solution Code (Python and Javascript)

### 1663H - Cross-Language Program

Solution
• +92

| Write comment?
 » 2 years ago, # | ← Rev. 3 →   +120 meme
 » 2 years ago, # |   +20 I did all possible word searches (normal, normal with diagonal, normal with diagonal with reverse, straight up grid BFS) for "MINOTAUR" and then for both "MINOTAUR" and "THESEUS" but didn't consider doing for just "THESEUS", fml
•  » » 2 years ago, # ^ |   +6 I did all possible word searches for theseus, got WA. Then I did only the forward-diagonal (i.e. [i0+k][j0+k]) search and got AC. Meanwhile the editorial says you had to do horizontal and vertical searches too. Who's in the right?
•  » » » 2 years ago, # ^ |   +8 Test cases were a bit weak, you had to do horizontal, vertical, and diagonal.
•  » » » » 2 years ago, # ^ |   0 IMO it is quite mean, that testcases had backwards-going "theseus" in them but were not considered safe. :D I checked for theseus first (but was also checking theseus backwards ord the other diagonal) but it only passed test 1. Then I checked for minotaur && !theseus as the unsafe condition and got to case 5.
•  » » 2 years ago, # ^ |   0 same, smh
 » 2 years ago, # |   +33 I printed "red panda" for problem A and got accepted???
•  » » 2 years ago, # ^ |   +43 Ha ha that's an easter egg :)Problem A accepts either "bucketpotato" or "red panda" (or various similar combinations).
 » 2 years ago, # |   +4 Is it normal that i wrote program writing "Red panda" for A?
 » 2 years ago, # |   0 what is meant by "AGC" in problem D?
•  » » 2 years ago, # ^ |   0 AGC -> AtCoder Grand Contest
•  » » » 2 years ago, # ^ |   0 Ah yes I totally forgot thanks!
»
2 years ago, # |
+39

### is it rated?

•  » » 2 years ago, # ^ | ← Rev. 2 →   +1 why did my rating change ._.
•  » » » 2 years ago, # ^ |   -9 Bro it is rated! No way lol
 » 2 years ago, # |   +71 What the actual f-k?https://codeforces.com/contest/1663/submission/152390392 import random print("YES" if random.randint(0, 100) % 2 else "NO") This gets AC in E.
•  » » 2 years ago, # ^ |   0 At first I thought that the generator used the same rng, but surely it doesn't work like this, right?
•  » » » 2 years ago, # ^ |   0 Maybe there are like only ~6 tests so it's not too hard for random to pass.
•  » » 2 years ago, # ^ |   +56 E has 9 tests, so in theory there's a 1/512 chance of this happening lol.
•  » » » 2 years ago, # ^ |   0 Rejudge and see how lucky they really are lmao
•  » » » 2 years ago, # ^ | ← Rev. 2 →   +8 Actually, if I recall correctly, CF re-runs your submission two more times in case of getting wrong answer. So the probability of failing all three attempts is $\frac{1}{8}$, probability of guessing answer in one test case is $\frac{7}{8}$, while you get AC with $\left(\frac{7}{8}\right)^9 \approx 0.3$ probability. Really worth a try!UPD: It seems that I confused WA and TLE solutions. While it is rather a well-known fact that CF re-runs TLE solutions, it is very strange to do it also with WA ones. Does CF really do it? Is it right to behave so?
•  » » » » 2 years ago, # ^ | ← Rev. 3 →   +26 CF doesn't seem to do it, because if codeforces actually did it and the chance of bypassing all 9 test with a random solution was 0.3, then with 10 tries i should get AC with 97.8% probability, but i don't. That only can mean that CF make only one attempt on failure or that i'm very unlucky :)
•  » » 2 years ago, # ^ |   +28 You should try playing poker.
•  » » 2 years ago, # ^ |   0 You have chance to pass any problem if you are lucky. Just pring random strings.
 » 2 years ago, # |   +18 can anyone tell me why I am getting WA in E? I did just like in editorial :(. My submission
•  » » 2 years ago, # ^ |   +18 wtf bro
•  » » 2 years ago, # ^ |   +28 The problem was that you accessed out-of-bounds memory; I have corrected your solution and it now gets AC: 152390393.
 » 2 years ago, # |   0 It is RATED! WTF???
•  » » 2 years ago, # ^ |   +4 I bet the rating changes will be reverted tomorrow :)
•  » » » 2 years ago, # ^ |   -10 It's obvious, but still very unexpected
 » 2 years ago, # |   +19 problem G Hard-coding strings solution code isn't available
 » 2 years ago, # |   +3 I guess the rating changes are only for today .
 » 2 years ago, # |   +34 Another Solution of Hconst struct { int x = 1;/*} = 3; begin end. {*/} a; int main() {} 
 » 2 years ago, # |   +15 Are the rating updates an April Fool's joke?
 » 2 years ago, # |   0 Submission Any particular reason why this code for C wasn't accepted?
•  » » 2 years ago, # ^ |   +30 Because you wrote ans=+x Instead of ans+=x
•  » » » 2 years ago, # ^ |   0 T_T
•  » » » » 2 years ago, # ^ |   0 Did it work?
•  » » » » » 2 years ago, # ^ |   0 yes T_T
•  » » » » » » 2 years ago, # ^ |   0 WOW
 » 2 years ago, # |   -8 Well, it is rated :D
 » 2 years ago, # | ← Rev. 2 →   -33 I write my user name in A get wrong Why
•  » » 2 years ago, # ^ |   0 The answer is either "BucketPotato" or "Red Panda"
 » 2 years ago, # |   +60 During the contest, after studying Pascal for an hour, I found a clumsy solution for H. codeconst long(*a)=new long[20]; #include int main() {puts("Hello World");} /*) :longint = 1; begin writeln('Hello World') end. */ I wonder what I was doing :<
 » 2 years ago, # | ← Rev. 2 →   0 How can I become a expert? It is so hard!!!!!!!!!! T_T
•  » » 22 months ago, # ^ |   0 Now you are a expert lol