Yesterday was my birthday. It was a good and fun birthday, and I got a new camera! Which was perfect, since I am starting to blog a lot more.

As of lately, I’ve been experimenting and embracing a lot of new web technologies. To list a few,

• Wordpress
• Twitter
• Adsense
• Analytics
• Feedburner
• Flickr

And I’m glad to say, so far its pretty good. With my new camera, I realized how much of a pain it would be, to actually upload every single image, one by one to my server, then link each one to my site. I tried wordpress’ gallery features, and it didn’t really do it for me. So I found a plugin called “Flickr Manager“, and decided to give it a try. You know what? I’m glad I did. Uploading to Flickr is so painless, and with this plugin, it makes it so easy to post to my blog!

I got this card today from a few of my classmates/students.

Its pretty cool, I especially like the inside. The girl’s mouth in the middle opens up and closes,
and I THINK (I think) she has a pair of boobs at the bottom.

Jaime Soosee asks,

can you guess what feature I drew?

What Is Twitter?

To Do: Figure out a way to format pictures more nicely in blog posts.

Due to the huge “geek-factor” associated with my blog, you can expect many snippets of code. I found this awesome plugin called wp-syntax that actually formats it and allows you to see colored syntax!

I love colored syntax when coding. Why? Aside from making it easier to read, its actually a VERY useful tool! Too many times, I’ve been able to fix my code before compiling/running, because the syntax I wrote wasn’t colored. I’d think to myself,

Wait a minute, how come this variable isn’t getting colored? I must of made a mistake somewhere!

Then I’m able to fix it right way. So awesome. Now, here’s hello world in many languages… with color support!

Python

     print "hello world!"

Java

      System.out.println("hello world!");

Javascript

     alert("hello world!");

Visual Basic

     MsgBox("hello world!")

C

     printf("hello world!");

C#

     System.Console.WriteLine("hello world!");

Scheme (one of my personal favourites!)

      (display "hello world!")

PHP

     <?php
         echo "Hello, world!";
     ?>

So awesome..

Every few years, I’d hear news of someone finding a prime number and getting awarded big bucks for doing so. Whenever I heard this kinda news, I’d think about how easy it would be to actually find them myself. I mean, it almost seemed too easy:

      1) Remove all even numbers
      2) Remove all multiples of 5
      3) Check all numbers ending in 3, 7, and 9 if they're prime or not.

So if you have a set of n numbers, taking out all the even numbers would leave you with n/2 numbers. Unfortunately, taking out the multiples of 5 didn’t do much, so its actually leaving you with 2n/5 numbers. My algorithm back in the day had also left out one important fact: How do I actually check if they’re prime?

With project euler, I was forced to actually re-evaluate my algorithm, and you know what? It failed spectacularly! However, it led me to something else. Its this SWEET algorithm called the “Sieve of Eratosthenes”.  Here’s how it goes:

     1) Make a list A of all numbers 1 to n.
     2) Make a list B to hold all the primes you find. The first item will be 2.
     3) Remove ALL multiples of 2 from list A.
     4) The first remaining number will be a prime. Add this to B.
     5) Grab that number and remove all multiples of it from list A.
     6) Repeat 4) and 5) until no numbers are left in List A.

It works perfectly (albiet pretty slow)  and it does its job: getting a list of n primes.  Apparently other people thought so themselves, so much in fact, that they actually wrote a poem about it!

Sift the Two’s and sift the Three’s,
The Sieve of Eratosthenes.
When the multiples sublime,
The numbers that remain are Prime.

Isn’t that cool? It even rhymes!

When I was learning “Computer and Network Security”, I actually learnt about another prime number generator. It uses a few complicated theories, namly Fermat’s little theorem and the Fermat primality test (aww man, I could of used this in my first algorithm!). Its good and it works, but its not as cool as the Sieve.

In other news, I can’t believe I just blogged about prime numbers. I am living up to my blog’s tagline already!

Being in computer science, you learn a lot of things. Specifically you learn ALOT of algorithms. Now, this isn’t a rant about proofs or theory, because I admit, they’re useful to a certain degree. They say “knowledge is power”, and THAT is the reason why I hate computer science so much sometimes! You KNOW those algorithms are useful, you know their potential, and you want to be able to use them, but many times, you can’t. I’m talking about search algorithms.

It just bugs me how I have to search for things everytime, and everytime I search. I feel so dirty brute-forcing things, when I could of found it in log(n) time. I’m a forgetful and lazy guy, so here’s my two biggest problems:

• I lose ALOT of things
• Book indexes suck too much to be useful

They say that,

Its always in the last place you look

If you really think about it, its actually true. Its because the list of locations to search is like an array list.

Think of a place, add to the list, search location. If I don't find it, add a new place to the list.

So when you actually find what you lost, you’re at the bottom of your list, which is the “last place” to look. There’s also the case where you cannot think of the right place to search, thus your list of locations can become infinitely large, driving you crazy searching all over!

So the next problem, book indexes sucking too much. Say I have a pile of papers or a book, and I want to look for a certain word/phrase. If I can remember what page its on, it takes constant time. If the index is actually useful, it takes constant time as well. Else, I pretty much have to scan through every one, thus brute-forcing again.

I guess what bugs me, is that I have to manually do it all. I’ve been spoiled by ctrl+f and google.

So those are problems that guys like me face. Is there actually a solution to spare me the brute-forcing?

I’ve had a few ideas running around in my head for a few years now.

What would solve the first problem? RFID tags + RFID tracker. Stick RFID tags on things you lose VERY often. So your keys, wallet, watches, glasses, belts, gloves, umbrellas, phones, etc… (yes…I lose these things all the time…). The RFID tracker stores each item in its database. So whenever you lose that item, you get the tracker, choose the item you wanna find. The RFID tracker then starts beeping, getting faster and faster as you’re getting closer and closer until BAM! You find it! They actually have an iphone app that maps the direction to your car (great for guys who can’t remember where they park… looking at you Tenniel). I’m thinking of actually taking up this project within the upcoming months.

What about the second problem? That’s actually a bit more complicated. I mean, you would need to invent a device that would be able to scan all these papers automatically (godforbid I scan them myself), at which point it would be easy to find text, just a simple search algorithm. Scanners actually exist that can capture text. Its called “Optical Character Recognition (OCR)” Software. Unfortunately, with my legendarily horrific handwritting, if even a human can’t read it, I can’t expect an algorithm to do any better. But there’s hope. Somewhat. The scanning paper problem can’t be solved, but the book one can be. Google Books.

Maybe there’s hope for me afterall?

So I’m geeking around the internet, like I usually do, when I stumble upon this awesome site. Project Euler! Pretty much, its a set of math questions that are ONLY solvable with a computer. So what does it mean for a young, industrious programmer like myself? Fun!

There’s 229 problems, and I’ve solved 27 so far… as you can see, I’ve got a long way to go.  Some of them are easy:

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.

Fairly easy to solve. Find all multiples of 3 or 5 and sum them up. Done. Now lets examine another problem:


Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, …

Find the sum of all the even-valued terms in the sequence which do not exceed four million.

This is where it gets complicated. The Fibonacci sequence actually grows pretty quick, which means the number will actually in the computer’s buffer, resulting in an “out of range” exception pretty quickly. Which means you can’t do a simple Fibonacci sequence linearly.

As the problems get more complicated, the chance that you can brute-force the answers become less likely. One of my favorite questions was the monopoly one:


In the game, Monopoly, find the three most popular squares when using two 4-sided dice.


I actually built a simulator to solve it, where I could change the dice easily. So I ran it for a 6-sided dice (like the ones we usually use), and found the following stats (10 million rolls):

1. Jail - 622228
2. Illinois Ave - 318336
3. New York Ave - 309739
4. GO - 308705
5. B&O Railroad - 307718
6. Reading Railroad - 297163
7. Tennessee Ave - 293212
8. Pennsylvania Railroad - 291143
9. Free Parking - 287501
10. Kentucky Ave - 283870
11. Water Works - 279720
12. St. James Place - 279563
13. Indiana Ave - 273179
14. Atlantic Ave - 269697
15. St Charles Place - 269678
16. Pacific Ave - 268251
17. Ventnor Ave - 267982
18. Boardwalk - 262216
19. North Carolina Ave - 261937
20. Electric Company - 259929
21. Marvin Gardens - 258568
22. Community Chest 2 - 258082
23. Pennsylvania Ave - 250309
24. Virginia Avenue - 246854
25. Short line - 242476
26. Community Chest 3 - 238379
27. States Ave - 237184
28. Vermont Ave - 232893
29. Income Tax 1 - 231599
30. Connecticut Ave - 230336
31. Oriental Ave - 226835
32. Park Place - 219057
33. Luxury Tax - 218509
34. Baltic Ave - 216265
35. Mediterranean Ave - 213695
36. Community Chest 1 - 189488
37. Chance 2 - 103436
38. Chance 1 - 87370
39. Chance 3 - 86898
40. Go To Jail - 0

Although, I may have to fix it up. From experience, I know going to jail shouldn’t be that low! All in all, these questions are a great way to practise programming when working with a new language. So try it out, you might enjoy it as much as I have.