Instagram Engineer Challenge solved with Javascript(feval.info)

Very neat. Makes me kind of embarrassed that I never got around to actually solving this challenge. I've had the web page open on my laptop since it first showed up on HN.

ronilanvor 15 Jahren

Mine from the weekend here: http://ronilan.com/instagram-unshredder/

reledivor 15 Jahren

I preferred yours. You at least gave some comments about the solution.

ekoszvor 15 Jahren

I wish I read the comments here first.

sktrdievor 15 Jahren

awesome! great job

coreyrecvlohevor 15 Jahren

Great job! Excellent coding style btw.

Mgcclvor 15 Jahren

This challenge is the first real life program I wrote with Haskell.

https://github.com/Mgccl/mgccl-haskell/blob/master/random/un... (so it seems I don't like to specify the type of my functions...)

Explanation is here: http://chaoxuprime.com/2011/11/a-solution-to-Instagram-engin...

nandemovor 15 Jahren

Very nice.

Care for some unsolicited hlint-like suggestions?

Why not simply this:

    img <- readImage "file.png" 
    -- instead of this?
    t <- readImage "file.png"
    let img = t

Why not this:

    map (y!!) x  
    foldr ((:).(y!!)) []　x　-- instead of this?

Note that a way of reading fold g [] is that replaces the list constructor (:) (aka cons) with g. So (:) as argument of fold is probably not idiomatic, since foldr (:) [] is the same as id.

Mgcclvor 15 Jahren

Thanks. hlint-like suggestions are always welcome.

I have no idea what was in my mind when I wrote

  foldr ((:).(y!!)) []　x

tikhonjvor 15 Jahren

Heh, I did the same thing. It took me much too long to figure out that I needed to call ilInit...

ricardobeatvor 15 Jahren

I (kind of) solved it with CoffeeScript but thought it wasn't a good idea to publish… if you do it's not a challenge anymore, is it?

https://github.com/ricardobeat/instagram-challenge

_gd3lvor 15 Jahren

Nice work!

touchcreamvor 15 Jahren

I solved it in ocaml, I only had this development environment this week end but it was fun. I didn't posted it on my blog but if someone wants it, just ask ;)

carnevalemvor 15 Jahren

You might also be interested in DARPA's similar challenge: http://www.shredderchallenge.com/

espesvor 15 Jahren

Or for a similar, easier task, problem 3 "life" from this year's FARIO: http://orac.amt.edu.au/fario/11/problems_en.pdf

Here's case 8 to give you an idea: http://i.imgur.com/1fFzO.png :P

Test data here: http://dl.dropbox.com/u/76985/life-all-linux.zip

swangvor 15 Jahren

So is this challenge over? I submitted an entry using Canvas as well but allowed users to drop image in from their desktop (only works in Chrome/Firefox though). Haven't heard from anyone at Instagram.

rjenkinsvor 15 Jahren

funny, that's exactly how mine works. Haven't heard anything either

rjenkinsvor 15 Jahren

Here's mine https://github.com/rjenkins/instagram-html5-unshredder

demo here http://memoization.com/unshred.html

asdfqwer1234vor 15 Jahren

so can someone actually explain how this works?

the-cakebossvor 15 Jahren

While I didn't look at how he did it, if I were to write something to do this, I would first locate each slice of the image. This could be accomplished using a rudimentary edge detection algorithm ( ie starting from the left, compare each column of pixels with the next, any large differences of course means an edge ). After that I might assign a weighted value to each edge of a slice, and then sort based upon those values.