Cody

Rafael S.T. Vieira

4
Rank
88
Badges
39494
Score
1 – 50 of 5,857

Rafael S.T. Vieira liked Problem 3102. Rumis Scorer 4

6 hours and 21 minutes ago

Rafael S.T. Vieira submitted Solution 3445303 to Problem 3102. Rumis Scorer 4

6 hours and 21 minutes ago

Rafael S.T. Vieira liked Problem 3101. Rumis Scorer 3

6 hours and 43 minutes ago

Rafael S.T. Vieira submitted Solution 3445063 to Problem 3101. Rumis Scorer 3

6 hours and 43 minutes ago

Rafael S.T. Vieira liked Problem 3100. Rumis Scorer 2

6 hours and 54 minutes ago

Rafael S.T. Vieira submitted Solution 3445003 to Problem 3100. Rumis Scorer 2

6 hours and 54 minutes ago

Rafael S.T. Vieira liked Problem 3099. Rumis Scorer 1

7 hours and 1 minute ago

Rafael S.T. Vieira submitted Solution 3444973 to Problem 3099. Rumis Scorer 1

7 hours and 1 minute ago

Rafael S.T. Vieira submitted a Comment to Problem 1701. Solve the picross! (Hard)

To any new challengers, know that only logic will not solve these puzzles. You will need some guessing, which means make the computer solve it as far as it can and then you, yes YOU, look at the picture (we humans can recognize the shape and finish the puzzle; the computer not so much). And, please, fell free to try some solvers out there.

7 hours and 40 minutes ago

Rafael S.T. Vieira received Community Group Solver badge for Paper-&-pencil Games

13 hours and 42 minutes ago

Rafael S.T. Vieira submitted a Comment to Problem 1701. Solve the picross! (Hard)

Solving a grid of 75x60 squares within Cody's time limit is extra hard. The greatest challenge is to find a fast code; recursion with backtracking no longer seems like a viable option. And I do hope the author is aware that nonograms are an NP-hard problem, which means there is no known fast algorithm to solve the general case: we have to build one for the specific cases of the test suite.

14 hours and 5 minutes ago

Rafael S.T. Vieira received Community Group Solver badge for Alphabet

21 hours and 2 minutes ago

Rafael S.T. Vieira submitted a Comment to Problem 1700. Solve the picross! (Easy)

Nope, it's not easy. A grid of 20x20 squares is already considered hard by regular players because we have to keep in mind several possible intersections between possible solutions.

on 27 Oct 2020 at 4:24

Rafael S.T. Vieira submitted a Comment to Problem 46943. Cipher the number

I am not sure this method can be called a cipher since there is probably no way to recover the original number. You should probably call it a hash.

on 26 Oct 2020 at 22:54

Rafael S.T. Vieira submitted a Comment to Problem 44971. Convert base 10 to base x (2-16)

Oh, the problem was with my algorithm, sorry. I am indeed using python's long int (for multiplication of large integers), but I was relying on str2num for some operations (which apparently introduced floats back in my code). After removing it, it worked out fine. PS: This new update knocked out some wrong solutions (including some of mine). Awesome. :)

on 26 Oct 2020 at 5:55

Rafael S.T. Vieira submitted a Comment to Problem 44964. Optimal Asymmetric Encryption Padding of message for RSA Cryptography

Thanks, David. I've struggled for a while with this problem but I've finally figured it out. First, although we don't use the encryption function from 7.1.1, we must create an output EM of length k-1 and apply a pad of 0 as the first character of EM (It was strange to see all hashes starting with 0). Next, I was confused with the Feistel Network, because my MGF from the previous problem wasn't working (an accepted solution), but I realized that you were probably using a hex input, instead of char (which is weird since the MGF function requires an Octect String as input), but anyway that solved it. :)

on 26 Oct 2020 at 5:46

Rafael S.T. Vieira submitted a Comment to Problem 2451. BLOCK x3 (Version 1)

https://noodlecake.com/games/blockblockblock/ (The game is no longer available at Google Play).

on 26 Oct 2020 at 3:11

Rafael S.T. Vieira submitted a Comment to Problem 1015. Polynomial Interpolation

FYI: The condition number of the Vandermonde coefficient matrix is just the norm of the matrix times the norm of its inverse. Cheers. PS: Wikipedia will just lead you to a paid wall. Don't waste time.

on 26 Oct 2020 at 2:47

Rafael S.T. Vieira submitted a Comment to Problem 44971. Convert base 10 to base x (2-16)

It seems the precision issues were indeed fixed. :)

on 25 Oct 2020 at 21:41

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