tungwaiyip.info

home

about me

links

my software

Media

Yucatán Photos

St Lucia Photos

Photo Album

Videos

Blog

< July 2010 >
SuMoTuWeThFrSa
     1 2 3
4 5 6 7 8 910
11121314151617
18192021222324
25262728293031

past articles »

Click for San Francisco, California Forecast

San Francisco, USA

 

Find Sophie Solution (Facebook Programming Puzzle)

This is the fourth and probably my last post about solving Facebook programming puzzle. The Find Sophie problem is a buffet (hardest) level puzzle. It is basically a variation of the traveling salesman problem. Traveling salesman is of course, a NP-complete problem. But before you throw up your hand, consider the puzzle refers to locations in your home where you may find a cat. Just how many locations are there. Let's say living room, dining room, bedroom, on the bed, under the desk, behind the curtain, ... etc. If Facebook is not very wicked, this puzzle should be bounded to a low hundreds of locations. This mean it is still possible to solve using some relatively simple search algorithm.

Here is the outline of my solution:

  1. Prepare to enumerate all paths.
  2. Prefer the local optimal during the search. Remember the best solution encountered so far.
  3. Prune the search tree. For example if the current best solution has a score of 50. When you are considering another path, as soon as its score exceed 50, you should abandon it.
  4. Improve the pruning by taking the additional score to complete the path into account. For example, if the current score of a partial path is S, the minimum score to complete the remaining walk is Rmin. Then if S+Rmin > best score, prune it.

Actually I have submitted the solution a few months ago. Only today do I find out I have not posted my solution in my blog. So I'm really speaking from my memory. I hope my plan is still accurate. Again my un-tidied code is available.

The other 3 facebook puzzles I have solved was posted below:

2010.07.22 [] - comments

 

 

blog comments powered by Disqus

past articles »

 

BBC News

 

Algeria passenger jet feared crashed (24 Jul 2014)

 

Gaza shelter attack 'kills 15' (24 Jul 2014)

 

UN sends 'unofficial' aid to Syria (24 Jul 2014)

 

Russia 'fired rockets into Ukraine' (24 Jul 2014)

 

Amazon reports quarterly loss (24 Jul 2014)

 

Sudan 'apostasy' woman meets Pope (24 Jul 2014)

 

Poland 'helped in CIA rendition' (24 Jul 2014)

 

Iraq MPs elect Massoum as president (24 Jul 2014)

 

Inquiry urged into two-hour execution (24 Jul 2014)

 

MSF allowed to resume Rakhine work (24 Jul 2014)

more »

 

Slashdot News for nerds, stuff that matters

 

Western US States Using Up Ground Water At an Alarming Rate (2014-07-24T22:17:00Z)

 

Chromebooks Are Outselling iPads In Schools (2014-07-24T21:35:00Z)

 

A Warm-Feeling Wooden Keyboard (Video) (2014-07-24T21:00:00Z)

 

ScummVM 1.7.0 Released (2014-07-24T20:21:00Z)

 

Laser Eye Surgery, Revisited 10 Years Later (2014-07-24T19:42:00Z)

 

Comcast Carrying 1Tbit/s of IPv6 Internet Traffic (2014-07-24T19:01:00Z)

 

Social Security Administration Joins Other Agencies With "IT Boondoggle" (2014-07-24T18:20:00Z)

 

Black Holes Not Black After All, Theorize Physicists (2014-07-24T17:38:00Z)

more »

 

TechPsychic Tech Rumors and Invented News

more »

 

SF Gate

 

Bay Area News (7 Jan 2012)

 

City Insider (11 Feb 2012)

 

Crime Scene (13 Feb 2012)

 

C.W Newius Column (10 Jan 2012)

 

C.W. Nevius Blog (11 Feb 2012)

 

Education News (10 Jan 2012)

 

KALW (11 Feb 2012)

 

Matier and Ross Blog (11 Feb 2012)

 

Senate tax inversion plan faces big challenges (24 Jul 2014)

 

Flywheel taxi app adds advance booking for airport trips (24 Jul 2014)

 

Ship traffic for July 24 (24 Jul 2014)

 

6 indicted in ring that hacked 1,000 StubHub users' accounts (24 Jul 2014)

 

Sanctions could push Russia into recession this year (24 Jul 2014)

 

Answers to questions on helping child buy a home (24 Jul 2014)

more »

 

Asia Times Online

 

CRISIS IN UKRAINE A chessboard drenched in blood (Wed 23 Jul 2014 11:00:00 GMT)

 

The charge of the Atlanticist Brigade (Wed 23 Jul 2014 11:00:00 GMT)

 

JOHN PILGER Orwell alive in Palestine, Ukraine (Wed 23 Jul 2014 11:00:00 GMT)

 

Hardliners maneuver over Iran talks extension (Wed 23 Jul 2014 11:00:00 GMT)

 

How US policies sealed Iraq's fate (Wed 23 Jul 2014 11:00:00 GMT)

 

Losses mount in China loan fraud (Wed 23 Jul 2014 11:00:00 GMT)

 

THE BEAR'S LAIR World War I still bad news (Wed 23 Jul 2014 11:00:00 GMT)

more »

 


Site feed Updated: 2014-Jul-24 16:00