Knight's Tour

I read it many years ago, it suddenly came into my mind, while I was working on Rainbowduino. Rainbowduino has a 8x8 RGB display matrix, I think is suitable to display Knight's tour solution.

Knight's tour (or Journey of Knight) is a mathematical problem. Is common exists in computer science study. The problem can be solved by a computer program.

Given a 8x8 chessboard, the knight is place on arbitrary point, find a route for the knight to travel all the 64 point without repeat according the the chess rule. That means, the knight will only visit each point once.

Journey of the knight is like Rubik cube for me, I don't know how to prove the solution exist. There is ready solution on the internet, just write the provided algorithm into codes.

The Warnsdorff's algorithm should be easy to understand. For any given point, there are maximum of 8 routes to choose. Choose the one with least possible routes.

Take the example from the Wikipedia. The start point has 6 routes to choose, each route has 3, 7, 7, 7, 5, 2 possible route. Choose the least possible route, which is 2.

By following the algorithm, I write a program which print out the following result:

14 27 16 51 12 29 34 63
17 52 13 28 55 62 11 30
26 15 54 59 50 33 64 35
53 18 25 56 61 58 31 10
24 1 60 49 32 45 36 47
19 40 21 44 57 48 9 6
2 23 42 39 4 7 46 37
41 20 3 22 43 38 5 8

iPad 2 selling fast in Malaysia

iPad 2 started to sell in Malaysia this morning 9am. Long queue at those popular Apple retail store like KLCC and Mid Valley.


Queue at Mid Valley Megamall

Seldom saw such an overwhelming crowd queue to pay for an electronic device, at least not for other tablet (for example Galaxy Tab). All available iPad 2 stock should be finish by today.

From what I heard, white color, 3G version and 32G model will be sold off much earlier. I heard from the iPad statistic, normally people go for the highest end (64G model) or the lowest end (16G model). Malaysian don't prefer the 64G model, may be pricing issue, and most people don't really need 64G storage.

iPad 2 price list for Malaysia:

Wifi version: 16g (RM1,499), 32g (RM1,799), 64g (RM2,099)
3G version: 16g (RM1,899), 32g (RM2,199), 64g (RM2,499)

In my opinion, the device is not expensive, is the accessaries which cost more. Apple has set the iPad price so low that, other competitors have to lower down their table price. That's why Samsung has lower down the Galaxy tab price to below RM2k compare with price at RM2,699 (without contract) when Galaxy tab first launched in Malaysia last year.

If you need USB or external storage support, get other tablet than iPad.

If you have apply leave today and couldn't get the iPad 2, may be you can spend your afternoon watching the Prince William and Catherine Middleton wedding live on TV, and order your iPad 2 through Apple online store.

iPad 2 will be available in more countries this week

Finally the news was officially announced by Apple. iPad 2 will be available in Hong Kong, Singapore, Malaysia and few more counties this week. Check the announcement here.

iPad 2 will be available in Hong Kong, Singapore and Malaysia this Friday 9am local time. Online order through Apple Store will be available 1am.

Win 7 total security alert

My friend's netbook pop out a win 7 total security alert, shows that it found 31 virus on the Windows 7 system.

A sample of the message looks like this:



After scanning the system with other anti-virus software, found nothing. Spend some more time search through the Internet, seems like the win 7 total security alert is the virus (malware). It gives false alarm about virus, spyware and malware on the system. It may appear as different name like Win7 Anti-virus, Win7 Anti-spyware, Win7 Internet Security 2011... check here.

How to remove? Use other virus/spyware/malware scanner. Manual step by step instruction is available as well, check the website here, here and here.

You can try use Superantispyware and Malwarebytes, a solution from Yahoo answer.

If you think the steps are too complicated, ask help from your friends, or you may consider re-install the Windows.

Apple quarterly earnings up 95%

Apple share price raise after announced their quarterly earnings has raised by 95% to 6 billions and revenue is 24.7 billions. Read the news here and here. Almost half of the sales contributed by iPhone sales.

Last year October (2010), Steve Jobs made a special appearance at Apple quarterly earnings conference, which he normally don't. That is the first Apple 20 billion quarter.

Last October, Apple share price is $300, just another 6 months pass, is $350 now. Some analysts target price at $450-$500, what do you think?