The Nineteenth Byte

Context A single suite from a deck of cards has its cards arranged in this order: A, 2, 3, 4, 5, 6, 7, 8, 9, T, J, Q, K. (We use the symbol T for 10). A bijective base b numeration, where b is a positive integer, is a bijective positional notation that makes use of b symbols with associated val...

Optimizer

10:30 AM

Whats with all these bi questions?

New Main Posts

10:41 AM

0

Q: Heaviest increasing subsequence

A subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements. A strictly increasing subsequence is a subsequence in which every element is bigger than the preceding one. The heaviest increasing subsequence of...

code-golf fastest-algorithm

Beta Decay

10:54 AM

Hey Pyth users, is this (K365-1c.!K*^KQ.!-KQ) the shortest I could make my program?

It's calculating the probability that two people share the same birthday in a group of people of size n

Maltysen

11:08 AM

@BetaDecay no, inline assign the K

Beta Decay

Oh that's cool

Pyth is so much nicer and cleaner than Golfscript

Maltysen

and here is the first number to cross a certain porbability: f>-1c.!K365*^KT.!-KTQ

run with .5 gives you 23

just 3 more chars

Beta Decay

So... Is that a for loop or a while loop?

Maltysen

a filter :)

Beta Decay

Ahh I see :)

Maltysen

11:13 AM

a filter with a numeric argument instead of a sequence returns the first value greater than the arg that passes the test

and the default for filter is 1

Beta Decay

Mm. I see

Is that the same with Python?

Maltysen

well, in python there filter return an iterator and calling next() on a filter does that. itertools.count() is an infinte sequence which is also useful for this.

Beta Decay

Ohh.

Maltysen

this reminds me: @orlp add 365 to your variable list under $y or something, it should be useful.

Beta Decay

Is 365 used that often?

Maltysen

11:26 AM

no, but we have ~90 variables to fill up

Beta Decay

Haha why not add 360 in there too

Useful for circle stuff

Maltysen

also, this should be shorter for birthday problem: csqMK^U365QlK

don't run it with 23 though, 2 at max, even then it doesn't finish online.

Beta Decay

Mm thanks :)

Maltysen

actually, .OqM^U365Q

but I haven't tested that one, and .O doesn't work online yet

Beta Decay

What does the capital P mean in Pmap and Ppow?

Does that separate it from the standard Python map and pow?

Maltysen

11:34 AM

yeah, and it stands for Pyth

Beta Decay

I see.

Maltysen

and also about that birthday problem pyth has builtins for combinations/permutations

-1c.PK365Q^KQ, brute force is still shorter though

Beta Decay

And those, I guess are the same as itertools.combinations and itertools.permutations

Maltysen

yeah, though on two ints, it calculates it analytically like you did with factorial.

And this has the benefit of working for n==0 and n>365

Beta Decay

n>365? Does it just return 1.0?

Maltysen

11:39 AM

yeah

flawr

1:40 PM

bonjour anyone here?

IntensifierDescriptorMan

Hello.

New Main Posts

2:07 PM

0

Q: Symbolic Differentiation of Polynomials

Symbolic Differentiation 1: Gone Coefishin' Task Write a program that takes in a polynomial in x from stdin (1 < deg(p) < 128) and differentiates it. The input polynomial will be a string of the following form: "a + bx + cx^2 + dx^3 +" ... where the coefficient of each term is an integer (-128

code-golf math string

trichoplax

2:23 PM

I couldn't find an explicit rule on bitcoin prizes, but there is some meta discussion on real world prizes which people can contribute to. — trichoplax 1 min ago

randomra

3:40 PM

@MartinBüttner regarding the Retina loops (github.com/mbuettner/retina/issues/24#issuecomment-124976185), as there is no mechanism to exit infinite loops I see very little reason not to exit if the string doesn't change. I like your proposed version. Mixed brackets look weird but that shouldn't be a major concern for a regex based language.

Martin Büttner

4:15 PM

@Dennis bring it on!

Dennis

The one time I beat Pyth, Retina beats me. No fair.

:P

Martin Büttner

;)

randomra

@MartinBüttner idk if unary is ok though, as OP said "Your output must have precisely the same form"

at least more motivation to implement unary-decimal conversion :P

Martin Büttner

@randomra Consensus in the linked post is that the unary default is only overridden if you specify that numbers have to be in decimal. I'd take his "Your output must have precisely the same form" to mean "the same form as the input" (regarding spaces, unary minus signs, 1-coefficients and omitted exponents)

randomra

right, it can be interpreted that way too

anyway I like to see well golfed Retina solutions which I can understand, and this could be one :)

trichoplax

4:29 PM

Would someone with Pyth knowledge like to offer some advice to this broken answer?

I don't have the knowledge to see where it's going wrong.

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