As a simple example: 8==D is a valid expression in many languages. A more impressive entry might be a program containing (_))::::::::::D, although I'm not sure how you could do this without syntax errors.
Your entry doesn't have to be a complete expression, but it does have to be part of a vali...
@Dennis When you wrap it in parens—({}+{})—, the first pair of braces cannot be interpreted as a block (or it would be a syntax error). So JS assumes it's an empty object instead. The second pair of braces couldn't be a block even outside of parens (+{ console.log('test'); } wouldn't make any sense), so it's always interpreted as an object. Applying unary + to an object results in NaN.
The word BANANA appears exactly once in this word search:
B A N A A N B B
A B A N A B A N
A N A B N N A A
N N B A A A N N
N A A N N N B A
A N N N B A N A
N A A B A N A N
B A N A N B B A
The word search above contains only one occurrence of the word BANANA, but a lot of similar words, like BANA...
@MartinBüttner Really? For Java? I don't think the paper would be publishable in anything above an undergrad journal, although I suppose I could give one of them a try if I make it sufficiently expository. More likely I'll put it up on my personal site and then link to it from OEIS.
I have an proposal I'd like to float: If you're going to post an answer in one language that's an exact golf of another language's answer, you should make it community wiki.
Pyth - 79 bytes
A translation of @AlexeyBurdin's answer. Can probably be golfed a lot more.
AzHmu++Gm1sH]Zd]Z,_zwK+lzlHJmm\ KK .e.eX@J+kY+-Yklz@" \/x"+byZHzjbmjk:d2_1:J1_2
Takes input as two numbers, newline separated. Explanation coming soon.
Try it online here.
@PeterTaylor Sorry, I normally don't Java. But isn't there some weird catch that I have to name the file after the class or something? That gets me every time.
x and y should refer to the two dot products are keeping track of, and returning to (0,0) in n steps means that they are both zero after adding n elements to the arrays
i'm not sure how that handles the "wrap-around" between the first step and the last step, or maybe i'm not thinking about that properly
i've made a bit of progress understanding the combinatorics. i can almost get matching results with (pari/gp) sum(i=0,n,if(i%2,0,binomial(i,i/2)^2*binomial(n,i)*4^(n-i))) -- it matches for odd n but not even n
the reasoning behind that expression is that, we iterate over the number of non-zero steps "i", which has to be even in order to get a path back to zero, and the horizontal and vertical components are independent 1d random walk problems, so binomial(i,i/2)^2, then there are binomial(n,i) ways to place those i moves, and then 4^(n-i) ways to choose the zero moves, but obviously there's a mistake somewhere
Hy guys. I'm new one on this, and this is my first programming puzzle & code golf question.
Take some time, and try to code, in your favourite programming language, this rhombus.
EXAMPLE
When i input 2 or 3, that your code output this:
* *
* * * *
* * *
* *
*
...
it may be something like: if you don't use every single node, then there's only one way to resolve the first and last steps, but if you use every node then there are two ways
you ask strange questions
you saw for yourself his code and my code give the same answers
i just told him about the expression that i found, and that i didn't understand why the extra binomial(n,n/2)^2 is needed, and linked him to that chat transcript, and said i would keep looking at it
i'm not sure. i think there is an obstacle that would need to be overcome, which is that we need to consider not just e.g. A[i] = A[i+1], but also A[i-1]
well for j=1 there are 4 reachable points and always exactly 1 way to get to each (ignoring the boundary). for j=2 there are 8 potentially reachable points, but only half of them are actually reachable depending on the sign of the previous array element, so i'm not sure how that would be reasoned about
(only talking about non-zero moves)
i have lack of experience here, but i was wondering whether we could use markov chains to get around that
(btw to add a bit to the light switch thing, apart from our stair lights the reason why the rest of them would be off for that picture is because if you flick it on, you can see a red spot at the top of the switch to indicate that it's on)
There [x^0](1/x + 2 + x)^n = [x^n](1 + 2x + x^2)^n = [x^n](1+x)^{2n} = C(2n, n) ways to move from (0) to (0) and there are a(n, i) sequences A that allows us to use exactly i X-moves and (n-i) Y-moves. So, c(n) = sum a(n, i) * C(2i, i) * C(2(n-i), n-i), where a(n, i) = [x^i]((x+1)^n + (x-i)^n))
well i didn't understand what the A[i] = A[i+1] check means when we are making the very first move, and so i was only thinking of the random walk part, treating it as an equivalent problem so that we could forget about A (but this is probably a mistake)
maybe, i will write a quick script for random walk brute force code, to see if n=2 gives 24 ( which is c(2) ), or 20 (which is my formula without the corrective term)
@Min_25 i am thinking that if B contains a 0 then the random walks can be put in 1-to-1 correspondence with the valid solutions, but if B contains no 0 then there are two ways to do that, and it would be provable by considering the boundary (first and last moves) in some way
i mean, two valid solutions for every valid random walk
@PeterTaylor I didn't realize my reopen vote would be binding or I wouldn't have "voted" given the conflict of interest. Still, I'm adamant that it's not a duplicate of the question you linked to, since producing the largest error message and the largest error output (combining all error messages) are two completely different things.
I am a complete amateur when it comes to the world of cooking.
My recent attempts to teach myself have unfortunately lead to me needing to ask:
How did I explode my saucepan?
I'd put some garlic/onion/olive oil in the saucepan and left it on low heat to soften on my electric hob. After about f...
the corrective term is related to a bug i made when writing the original dp code; i had for A in 1,-1 instead of for A in ( (1,-1) if N else [a] ), and printing n/2 for that code gives same sequence of numbers (the formula without the corrective term)
@Lembik i can see that it is the same as if(n%2 != i%2, 0, 2*binomial(n,i)) but i don't see how it gives the number of valid A sequences. i guess i could have asked Min_25 but i didn't want to bother him with having to explain things that are supposed to be obvious, if that makes sense
i mean, the number of A sequences with the property he specified
i'm not used to using polcoeffs to solve counting problems, my combinatorics experience is not enough
@Dennis meta.codegolf.stackexchange.com/q/777/194 If there's an existing question, all of whose answers are good answers to the new one, and one of which only requires minor modification to be unbeatable in the new one, then by the standards of this site it's a dupe.
There are sometimes grey areas, but this wasn't one.
ok i had seen this before but forgotten -- you can use e.g. [x^m]( (1+x+x^2+x^3) * (1+x+x^2) * (1+x) ) to find the number of ways to choose m balls if you are given e.g. 3 blue balls, 2 green balls, and 1 yellow ball
This challenge is about writing code to solve the following problem.
Given two strings A and B, your code should output the start and end indices of a substring of A with the following properties.
The substring of A should also match some substring of B.
There should be no longer substring of ...
@MartinBüttner I look forward to reading that! But then I already knew Peter Taylor was a genius. I didn't know we had more than one :) I also really like the collaborative effort to solve a hard problem.
(apologies to everyone who is clearly a genius who I have left out by accident)
The word BANANA appears exactly once in this word search:
B A N A A N B B
A B A N A B A N
A N A B N N A A
N N B A A A N N
N A A N N N B A
A N N N B A N A
N A A B A N A N
B A N A N B B A
The word search above contains only one occurrence of the word BANANA, but a lot of similar words, like BANA...
Pyth - 79 bytes
A translation of @AlexeyBurdin's answer. Can probably be golfed a lot more.
AzHmu++Gm1sH]Zd]Z,_zwK+lzlHJmm\ KK .e.eX@J+kY+-Yklz@" \/x"+byZHzjbmjk:d2_1:J1_2
Takes input as two numbers, newline separated. Explanation coming soon.
Try it online here.
Hy guys. I'm new one on this, and this is my first programming puzzle & code golf question.
Take some time, and try to code, in your favourite programming language, this rhombus.
EXAMPLE
When i input 2 or 3, that your code output this:
* *
* * * *
* * *
* *
*
...
This challenge is about writing code to solve the following problem.
Given two strings A and B, your code should output the start and end indices of a substring of A with the following properties.
The substring of A should also match some substring of B.
There should be no longer substring of ...
