Archive for April, 2010

Fixing the Motorola Droid Battery Cover

Step 0: Own a Motorola Droid.
Step 1: Get kind of annoyed by the battery cover slipping off at inconvenient times. Be sure not to get so annoyed that you actually take steps to fix the issue.
Step 2: Go drinking with some friends at your local on an idle Thursday night.
Step 3: During a heated game of shuffleboard, accidentally slosh your beer on the pocket where you carry your phone.
Step 4: Swear.
Step 5: Wipe the phone off with a paper towel.
Step 6: Swear some more.
Step 7: Go back to playing shuffleboard.
Step 8: Wake up the next morning, carefully clean the Droid’s screen and keyboard.
Step 9: Notice after a few days that the battery cover is stuck shut with dried beer.

N.B.: I performed the above steps with (I believe) a porter. Not sure what kind. Not sure if the variety of beer matters.

Also, this post is just one man’s method. My phone weathered it fine, but yours might not. This will probably void your warranty. It might destroy your phone. Hell, it might give you scabies or an unhealthy obsession with the Beta Band.

Whatever happens, you undertake the above steps at your own risk. I make no promises, guarantees, avowals, or assertions as to the safety and efficacy of the above method. If you mess up your phone, it’s on your head.

I will, however, say that my battery cover still stays in place quite nicely.


Posting’s going to be abnormally slow here the next two weeks. I’m currently ramping up into a new project at work while another one is just winding down. While there’s overlap, I’ll probably be pretty busy. There’s also some Good Things in the works about which I’m reticent. I’ll post more about them if they pan out.

I do, however, have a few posts in the works about a variety of things; Quines and the CLR and hacker drama, oh my!

So stay tuned. But while you’re staying tuned, here’s an intersting quandary:

So the game Flood-It (to which I’m fair addicted) has recently been proved NP-Hard. The game is fairly simple. From the abstract of the linked article:

“In this game the player is given an n by n board of tiles where each tile is allocated one of c colours. The goal is to make the colours of all tiles equal via the shortest possible sequence of flooding operations. In the standard version, a flooding operation consists of the player choosing a colour k, which then changes the colour of all the tiles in the monochromatic region connected to the top left tile to k. After this operation has been performed, neighbouring regions which are already of the chosen colour k will then also become connected, thereby extending the monochromatic region of the board.”

So my question: what constraint of the above problem, other than finding the shortest sequence, could one relax or eliminate to move this problem from NP into P? I strongly suspect that, were a player allowed to choose their starting square after having seen the initial board coloring, that all board configurations would be solvable in P. I haven’t proved this yet, though, so I may very well be wrong.


Not Quite Constant

Interesting tidbit I found while brushing up on Big-O analysis – apparently some methods are O(a(m,n)) where a(m,n) is the inverse Ackerman function. It’s also sometimes written as a(n), if the two inputs are equal. This function does grow (so it’s worse than constant time) but it grows so slowly that it can almost be ignored.

a(n) will not grow larger than 5 for any number which can be written in the physical universe.

An example of an algorithm that demonstrates this is Chazelle’s algorithm for minimum spanning trees [pdf], which is O(e*a(e,v)) where e is the number of edges in the graph and v is the number of vertices. So it’s functionally O(e), but not quite.

Interesting, if useless.

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Magic Blue Smoke

House Rules:

1.) Carry out your own dead.
2.) No opium smoking in the elevators.
3.) In Competitions, during gunfire or while bombs are falling, players may take cover without penalty for ceasing play.
4.) A player whose stroke is affected by the simultaneous explosion of a bomb may play another ball from the same place.
4a.) Penalty one stroke.
5.) Pilsner should be in Roman type, and begin with a capital.
6.) Keep Calm and Kill It with Fire.
7.) Spammers will be fed to the Crabipede.