TI-BASIC competition

[PT_]

Does the parser need to throw an error if the string does not contain a valid sentence or the string should be assumed valid ?
E.g., can a string contain 3(+5 ?
This considerably changes the time...

You may assume the string is correct

[PT_]

Make 24 is a very simple game, with only 4 numbers trying to make 24, but programming is a lot harder... In this task, it is your task you output the string, which makes 24 if you call expr(<string>), of course with only 4 given numbers. I know; there are tons of them on the Internet, but you still need to remember that speed is more important than size, and that seems to be sometimes the problem

Task 3:
Output a string with 4 numbers and any mathematical token that makes 24 if you call expr(<string>). Input is both in Ans and L1 and contains the 4 numbers from 1-9 to create 24. Note: you may assume you CAN make 24 with the input, so it is not impossible. Output should be a string in Str1 which contains the string. If someone call expr(Str1), it should return 24. Limitations: no extra numbers. You can use any TI-BASIC command, as far as you may not add numbers to it (like +1, ^2). sqrt( is still allowed.
I'm looking forward to see your solutions, and if you don't have finished task #2 yet, please don't forget it

Good luck everyone!

[PT_]

Maybe it's time for a sneak peek at task #4 to motivate you all to finish this competition (5 tasks)?

- It's not only speed and size, but more than that...
- The more the size, the less the size...
- Too large, too small...
- At the end, you're not at the end...

Good luck everyone for solving these tasks!

[PT_]

TI-BASIC.

Integers.

Lists.

Matrices.

Do you know that they take up a bunch of memory in the RAM? One single TI-OS variable is 18 bytes, a list is 12+9*[dimension], and matrices 11+9*[width]*[height]. And often is that not necessary. Many people have booleans in their programs, like not(A->A. You can store that in only 1 bit, instead of 18*8=144 bits....
And that is what this task is for. You need to compress data as much as possible, and then you're still not at the end. A very simple example of compressing, is storing booleans as bits, and not as 9-byte floating numbers, which saves much free space in RAM. Your task is to create a lossless compression algorithm (lossless = you can restore it to the original data).

Task #4:
Write an algorithm that compresses data without losing stuff. The input is a string in both Str1 and Ans, which contains a normal English text with these possible characters: ABCDEFGHIJKLMNOPQRSTUVWXYZ_.,. Not more, not less (no lowercase letters!). The length is about 100 characters. Output is very simple: it can be anything, what you prefer, but remember what I said about integers, lists and matrices, which takes up much space. You may use ANY BASIC-command, because there is no compress-command . You only need the compression algorithm for scoring, but you should be able to decompress it as well! I say this, because otherwise people could say their algorithms are lossless, but in the meantime...

Anyway, to give you enough time, I decided to make #5 easy. In 2 weeks, this competition will be closed, so be sure to start today!

Score:
Not only speed and size is important, the compressed size too (without header!!!)
Ratio speed:compressed_size:size = 3:5:1

This would be an example as an input:

Code: Select all

"CHRISTOPHER LIVES IN NEW YORK CITY, ONE OF HIS SEVERAL LOVES ALONG WITH CALCULATORS, TECHNOLOGY, AND TRAINS."->Str1
prgmCOMPRESS

Good luck everyone, and have fun!

[PT_]

Last summer we had great news: TI releases a new color calculator, the TI-84+CE-T! Everyone happy, but not the ASM experts, because they found out that it was signed with a 2048-bit signing key, which is impossible to crack with the current possibilities. That is why they never can create Apps for the CE, until TI releases the SDK. Maybe we could help to crack that enormous number with BASIC?

The way to crack that key, is to find the factors of that key, such that P*Q=[signing key]. In the reverse, if you know the key, you can theoretically find P and Q, but that takes ages. That is what this task is about. You have to factor a number as fast as possible. I made this, because factorization is a pain and takes much time, especially with large numbers.

Task 5
Given the input in both N and Ans, output the two factors in L1 as a list. No limitations, and you may assume that number is withing the bounds of TI-BASIC.

Example: 5680842901 would be 60869*93329.

Good luck all and speed is still very important!




Submission
Now that the last task is being posted, you can submit your entries. Submit your entries by emailing them, in a ZIP file, to basiccompetition@gmail.com . Any entry before March 22th 11:59:59 pm GMT will be accepted, entries after that will be removed. Be sure to provide your Cemetech username in the subject or body of the email so we know who you are! Everyone can submit as many entries as they want, the last one will always be tested. If you have more programs for a task, please say which program is the main.

Testing
This is how I will test all the entries. I will first reset my whole calculator, including the Archive. Next, I transfer my timing program to the calculator, and after that, all the inputs. Finally, after that, I will transfer your program, so the VAT entry is for everyone equal.
I will test all the entries 3 times, and the speed is the average of that 3. You may assume no variable exists, without the input variable(s). I will measure the time with always the same program, upto 3 digits, so 4.193 can be the time for someone.
If you think it is not fair that I test my own programs, please pm me, and we will look for a solution

I will try to test all the programs as fast as possible, but it's dependant of the entries how many time that takes

I hope you all enjoy this competition, and it's not only for competing, but also for writing algorithms for yourself.

Summary of the 5 tasks:

1. Sort a list
2. Express a string
3. Make 24 with 4 numbers
4. Compress a string
5. Factorize a large number

I hope that there are many, many entries coming!

If you have still questions, please post or pm me

Good luck in the last week!

[PT_]

Exactly one-day-and-some-hours to go, people!
If you haven't submitted your entries yet, don't hesitate to do so! Even if you don't have all the 5 (or more) programs, you can earn points.

[PT_]

And still 6 hours to go! I've received some entries, but these are still much less as the participants
Even if you don't have all the 5 programs, you can submit your entries!

[noelnadal]

By the way, how do you ensure that for task 4 our code can be decompressed ? Do we have to give you an explanation along with our program ?

[PT_]

By the way, how do you ensure that for task 4 our code can be decompressed ? Do we have to give you an explanation along with our program ?

As far as I've seen, all the people who sent task #4 explained how to decompress.

[noelnadal]

Ok, thanks.