Random things I've written

Over the weekend, I was debugging a strange issue on my site built with Vue.js. There is `input-text` component which wraps an `input` element. When I type, after the first character, the focus wi

Today, I've encountered a counter-intuitive behaviour around `null` in Postgresql. `SELECT * FROM users WHERE facebook_id != 123` will not match any row whose `facebook_id` is `null`. Why? What?

For some time, I've been using Polymer.js extensively. I want to write about its quirks. Some of them are deal-breakers for shipping a site to production. Here they are: ### The three states of if-

I have been trying to get Playframework to use memory less than 512MB for a while. The reason for targeting 512MB is because it's the cheapest dyno on Heroku. The 1GB dyno costs twice. The site is

Here's a reference [Stackoverflow question](https://stackoverflow.com/questions/29701517/playframework-testing-uploading-file-in-fake-request-errors). It happens when I try to test a controller wit

Here's the proof of concept: [https://jsfiddle.net/1gqpe1bu/](https://jsfiddle.net/1gqpe1bu/). In summary, a negative condition in PolymerJS 2 have 3 states: `true`, `false`, and `undefined`. `

I've been working on upgrading [clusterfuzz.com](https://clusterfuzz.com) from PolymerJS 1.0 to 2.0. It has been quite challenging because there are a bunch of breaking changes. Anyway, I've noticed t

I've encountered the case where SocketHandler on windows under a separate `multiprocessing.Process` doesn't seem to work. The proof of concept here takes a significant part of code from: [https://

It's surprisingly non-trivial to detect the Rails migration failure during the deployment. The problem comes from the fact that `git push` doesn't exit with 1 if the migration fails. It took me a whil

Our team has recently found a corrupted PYC (compiled Python) file on windows. I've found the issue because it complained that certain obvious methods didn't exist; it was soo improbable that I nee

Overall, [Ergodox EZ](https://ergodox-ez.com/) felt great. However, I think the keys for the thumbs are not really ergonomic. They are basically out of reach. I think I'll just wait for [the keyboardi

This might be because the cache is not invalidated after installing a new package. Just run `hash -r` to update cache.

This is because the file is deleted but some processes haven't closed the file yet. So, these deleted files are still maintained in the directory, and `du` doesn't read these ghost files. We can

We need to be careful with it because it'll immediately open the file. If we want it to open the log file lazily, then we can add `delay=False` for `__init__`.

I have no idea why... but I guess it's related to creating a new session. The below fails with `sudo: no tty present and no askpass program specified`: ``` import os import sys import subprocess

I misunderstood how `stdin` worked. * I thought it would be difficult, for python, to run an interactive child process because we would need to proxy `stdin` and `stdout`. * I thought that `stdin

After reading [this post](https://thraxil.org/users/anders/posts/2008/03/13/Subprocess-Hanging-PIPE-is-your-enemy/), I couldn't believe that it was gonna be true. So, I setup my little experiment.

This is because the module that you are using require `connection: local`; But you are using `connection: ssh`.

As of now (14 April 2017), please use [Pants](http://www.pantsbuild.org/) instead of [Bazel](https://bazel.build/). So, in the past few days, I was exploring a build system for our Python project.

We can utilize `new_http_archive`. In `WORKSPACE`, we have: ``` new_http_archive( name='yaml', url='https://pypi.python.org/packages/4a/85/db5a2df477072b2902b0eb892feb37d88ac635d36245a72

Basically, we can hook into `setup.py` to do that. The code looks like this: [https://github.com/google/clusterfuzz-tools/pull/150/files](https://github.com/google/clusterfuzz-tools/pull/150/files).

I have been experimenting with Ansible with our remote 120 machines. I want to update them simultaneously. Forks = 1 ----------------- With `forks = 1`, Ansible playbook's is super reliable. Th

Setting up multi-projects in SBT requires 2 wisdoms: 1. We might need both `aggregate` and `dependsOn`. `aggregate` means that a task (e.g. compile) is performed in the main project as well as the

For example, I want different environments for [Flyway](https://flywaydb.org/)'s SBT tasks. Here is how we can have different variables for 2 different environments: ``` lazy val ProdConfig = conf

Basically, we can just go to a subfolder and run `git init`. The subfolder's files will be removed from the current git repo. The parent git repo records which child git repo's commit it uses. T

I have been experimenting with [scala.util.parsing](https://github.com/scala/scala-parser-combinators). I think it's capable of building an interpreter for a language like Ruby. The library is so p

Today I've been debugging an issue with virtualenv. The gist of the problem is that `python -S`'s behaviours in virtualenv and in global python do not match. In virtualenv, this causes an inexpli

Here's the secret: [https://issuetracker.google.com/issues/35898987](https://issuetracker.google.com/issues/35898987) To sum it up, the request body must be a JSON object containing the field `queu

This is amazing. Our index is ~100GB right now. Datastore is working fine without any issue.

It's a bad idea to support jumping to an arbitrary page when using App Engine Datastore. In fact, it's a bad idea for any database. For most databases, when we want to jump to, say, page 100 where

The logs didn't show up in Log Viewer. After I change `time` to `created`, the logs show up properly. Weird.

It is a bit counter-intuitive for programmers... but it is said right there in (the documentation)[https://cloud.google.com/bigquery/docs/reference/standard-sql/functions-and-operators#unix_seconds]:

We have a cron task that takes around 3-4 minutes to finish. I was worried a bit that, if my cron schedule is too frequent, two jobs might run concurrently. That might create inconsistent records in o

The article is here: [https://cloud.google.com/appengine/articles/indexselection](https://cloud.google.com/appengine/articles/indexselection) I thought the algorithm was a god send that allowed me

Runit doesn't rely on PID. It runs process in the foreground. This is more appropriate for a python app. However, for an application that manages its own PID or has its own init.d's script, Monit i

I've found that it's very strange that [gcloud-sdk](https://cloud.google.com/sdk/downloads) contains a client secret. One public client secret is in `lib/googlecloudsdk/core/config.py` on the line 165

We can authenticate user using an access token. Calling OAuth Google API to get the email from an access token is not difficult. There are a myriad of options [here](https://developers.google.com/iden

In a flexible App Engine instance, [the documentation](https://cloud.google.com/appengine/docs/flexible/custom-runtimes/build) states that we can output to STDOUT and STDERR from our app, and the outp

The crucial part is to set the header `Authorization` correctly. Therefore, we need to include `google-api-client` first. The below lines should be added to `build.sbt`: ``` libraryDependencies ++

I've been thinking about my English pronunciation issue since I've moved to Bay Area (from Thailand) in 2012. I can't seem to speak English properly. There were many moments that made me feel bad

I've been experimented with [runit](http://smarden.org/runit/). It's a great way to supervise a long-lived application. I don't want to use `nohup` anymore. There are many good tutorials. I've foun

Since I've joined Google, I have been writing Python 2.7 intensely. I've found that the language is ugly. Here are some specific points: ### Calling a super class' method requires us to repeat th

We can deploy Play Framework (Scala) on flexible custom-runtime App Engine. In fact, we can deploy anything that serves HTTP traffic on the port 8080 on flexible custom-runtime App Engine. The only re

Don't be lazy and please verify the etag of a downloaded file. For example, https://chromedriver.storage.googleapis.com/index.html?path=2.26/ shows etags of each file. Or we can get etag from a re

Appengine normally have an admin UI for performing a backup here: https://ah-builtin-python-bundle-dot-<app-id>.appspot.com/_ah/datastore_admin And it's great. I can perform a backup on __all__ ent

During the thanksgiving weekend, I have been experimenting with SaltStack on Google Compute Engine. It takes some imagination to setup the SaltStack masterful architecture. After reading and trying

Here's the powershell script to install OpenSSH on Windows: ``` # Create helpers. $shell = new-object -com shell.application Function unzip($fileName, $folder = "c:\") { $zip = $shell.NameSpa

Let's assume we have a file with a really long path (longer than 260 characters). Let's name is `c:\longpath\test.txt`. Here's how `os.path.exists(..)` behaves: * `os.path.exists('\\?\c:\longpath\t

Windows strangely imposes a limit on a path length. The limit is 260 characters. Now many answers on Stackoverflow suggests we can prefix a path with \\?\ in order to bypass the limit. It works

Writing unit tests for Appengine's taskqueue and deferred involves stubbing a queue and processing items in the queue. It's a bit difficult to find the correct APIs to do these things. So, here's

I have been explore a few different way. There are a few things to mention: 1. Using `shell.application` with `CopyHere` doesn't work well because sometimes a directory entry is not in the zip file

[Google Cloud Storage](https://cloud.google.com/storage) offers hosting static files. Or they call it durable and highly available object storage. However, when we download a file from Google Cloud

I have been googled around for this technique for like a week. I have been using the wrong keyword. I was googling for "Shortcut to terminal ubuntu". And I found nothing. After switching the keywor

My wife and I have moved to Dillon (in Colorado) this winter to learn skiing. The town is perfect as it is 15-minutes drive to 3 ski resorts, Keystone, Arapahoe Basin, and Breckenridge. It's also only

This was the second time in my life that I went through interviews with tech companies in the Bay Area. Here’s what I’ve learned: ### Green card does help a lot The early question that every rec

To everyone who's about to get a job with H-1B. You can start by asking about the policy around sponsoring green card. Some companies wait 1 year, some wait until you are a senior engineer, some start

We are about to go on a long trip. We'll drive from Dillon, Colorado to San Francisco, California. It's around 1,200 miles. I wanted to make sure that my car is ready for the trip. And that was when I

Problem is getting more difficult. I cannot solve this problem at all, not even the small data set. I've realised that some of the sets will contain only one element. Therefore, I can pick some ele

I cannot solve this problem because I cannot write a proof. That actually happens quite a lot. I can imagine an axiom which turns out to be wrong because I cannot write a fucking proof. For this pr

At first, I was thinking that either min salary or max salary should be removed in order to reduce the difference. That sounds easy enough. But finding min/max and removing a node (with its children)

I cannot understand the solution for the large dataset. However, for the small dataset, it's quite simple. We just brute-force the damn thing. There's a little twist in the brute-force; If it's Han

__The answer is__ 0.1 and 0.2 cannot be represented as finite in the base 2 system. They are repeating decimals in the base 2 system. Since computer has limited memory and use the base 2 system,

A problem that must be solved with a greedy algorithm is usually a very difficult one. For this problem, it turns out that we can devise a greedy algorithm to solve it. However, a greedy algorithm

This one is pretty difficult. I cannot solve it. However, I've realised a bunch of clues that the solution must be DP. First of all, let's make this clear. __When Diana skips a turn, it means that

First, we have to know that: > It's always better for Arnar to segment the devices into 3 segments (better than 2 segments) There are exceptions: if there's only 1 device, then Solveig gets it.

Please note that this is MongoDB 2.6.11. I have been trying to optimise MongoDB, and I have figured out how indexing for `$ne` works. Here's one gotcha: __MongoDB will decide to indexes based on

Note: this is to show the power of macros. If you need this feature, just use a case class. As an exercise to learn macros, I have been trying to implement Ruby's attr_accessor with Scala's macros.

I'd like to build a better log function. You know, normally, you have to log variables like this: ```scala log(s"Some msg [count = ${count}]") ``` You can see that `count` is redundant. We sho

Note: git's version is 2.3.2 (Apple Git-55) I have encountered a way to lose a commit by accident. If you're using a combination of git-merge, git-rebase, and git-amend, you should read on. I ha

I was stuck at this problem for almost 5 hours. It's difficult to debug because of a long test cycle. I've found that, when a command in the `script` block fails, the `after_script` block is not ru

When changing a server, I've got an authorisation error from Google API that looks like this: ``` { "error" : "invalid_grant" } ``` This is because the date/time on the server is not corre

Here's a short code for reading command line arguments: ```scala def readCommandArgs( args: List[String], argsSoFar: List[(String, List[String])] ): List[(String, List[String])] = {

This is because Play computed checksum and store it in the database. If you change it, Play will try to apply DOWNs until the changed file and apply UPs. That's very very dangerous.

When we run a command, we should pipe it to the `tee` program: ``` run_some_command | tee /tmp/some_temp_file ``` Then, we can open another terminal and run: ``` tail -f /tmp/some_temp_fil

When I setup a new user on a server, I always have a problem with logging in with the new user using its public key. Today I've found a way to debug it by stopping the SSH service and starting it w

[The 4 problems for the qualification round](https://code.google.com/codejam/contest/6224486/dashboard#s=p0) are quite interesting. The style of a problem is a bit different from the TopCoder's one; a

For this problem, I was lost a few times, and the obstacles made me stuck for a very long time. The first obstacle was that I didn't formulate the problem properly. After deciding to formulate it,

I've just finished the book "Get out of your own way". It's embarrassing to read a book similar to this one. The book explains 40 destructive behaviours and offers ways to overcome them. A destructive

The problem editorial is here: [http://apps.topcoder.com/wiki/display/tc/SRM+651#FoxConnection3](http://apps.topcoder.com/wiki/display/tc/SRM+651#FoxConnection3) I couldn't solve this problem on my

I've just returned my badge and my laptop today. I've walked out of the Twitter office for the last time. I couldn't believe that today would eventually come. The feeling was surreal. I feel sad and e

Today, I've just implemented a state machine that contains another state machine. It confused the heck out of me. Normally, a state machine can be implemented with a 2-dimensional array pretty easi

I was building a state machine in Scala, and I want it to be an immutable state machine, where all nodes are immutable. It's actually a bit interesting how we can achieve it in Scala. Let's define

I've been reading the book [Foundations of Statistical Natural Language Processing](http://nlp.stanford.edu/fsnlp/). I should have read it a long time ago, so I've decided to read cover-to-cover. It's

It's a bit of a dance because Heroku set the environment variable ```DATABASE_URL``` that contains username and password. So, you will need to force the driver to read username and password from the U

This blog is built with Play 2. Play 2 is kind of cool, and I'm in love with Scala (over Ruby). Nevertheless, I still love Ruby for building a command-line tool. At least, I prefer Ruby over Py

It turns out there are 2 ctags binaries on OSX. One is from XCode toolchains. The other one I install it from brew. Be careful with it. Here's the configuration in ~/.ctags that makes ctags for

Always do this! otherwise, character rendering will look really odd.

That's because we need to exit all tmux's sessions and restart it.

I'm gonna learn vim seriously now. I believe this can make me work faster. There are 2 things I want to achieve: 1. Code on a remote machine. It will be faster because the deployment will be super fa

I just installed oh-my-zsh today and upgrade TotalTerminal (TotalTerminal's previous version is broken on my Mac) Here are the settings I use: ```bindkey "\C-f" vi-forward-blank-word``` and ```bindk

As I am learning all the bash shortcuts, I've found that moving forward and backward by words are not very useful. I don't normally want that. Moving forward and backward by spaces seem to be more va

Yesterday I was having a great idea of instantiating an ArrayList once and re-use it instead of instantiate an array of int[] everytime. It turns out that the performance is much worse. There are 2 p

OpenJDK has pretty decent Thai tokenization library. Nevertheless, there are some quick wins that can be implemented. For example, there are some patterns that are not sensible whatsoever. See this r

This week is the Twitter's Hackweek. Basically, we are allowed to do/build whatever we would like to. So, I've decided to learn more about Thai tokenization (or Thai word segmentation) in OpenJDK. He

I have been very confused by the serialization issues because I was trying to use the Command pattern and try to attach external dependencies (e.g. a finagle client, which is a network-thingy client)

It would prevent an object from being implicitly converted. I have a problem with instantiate a class within FunSpec because it would be implicitly converted. After it was implicitly converted, it ha

Yeah, it will just become nil.

I have researched about how to daemonize my Rake task and how I can use it in my deployment script. I need a background task that is running all the time (not a cron job) and it should be restarted w

THIS IS NOT GOOD ANYMORE. The gem `daemons` doesn't seem to be well-maintained, and Ruby 2.0 has a cleaner way of daemonizing. --------- So, I have been stuck with daemonizing a rake task for a whil

I forgot how to pick up a new skill because I haven't really learned anything new skill anymore. I just took a ski lesson a few days back; It took me like a while to know how to slow down on ski with

Encountered 2 of them: * ByteBuffer * SimpleDateFormat The error message usually doesn't make any sense. The input format is incorrect is one of them (even when you print it out, it looks correct)

You may use `yes > /dev/null &` What it does is that it prints 'y' repetitively. Running multiple of these things will max out your CPU Please see `man yes`

You can bypass that by using: * REPLACE * INSERT ... ON DUPLICATE KEY UPDATE * INSERT IGNORE (a bad one because it also ignores other errors)

I request to read data for 6 months. I guess it was way too big. If it is too big, you will get this obscure exception: ``` Failure Info:Job initialization failed: java.io.IOException: Split metadata

When running a bash command from Ruby with a environment variable. Don't do this: ``` system('GARUDA_ENV=prod echo $GARUDA_ENV') ``` It won't work... Please do this ``` system({"GARUDA_ENV" => "pro

If you want to hardcode some userIds, you can use this source: IterableSource. ``` IterableSource(Seq(1, 2, 3), 'user_id).read ```

We can optimize on joining sources; Say we have the sources, A and B. If A is relatively of the same size as B, we use the normal join (e.g. joinWithSmaller). If A is much much smaller than B, but A

You can edit the list of sudoers (the users who can sudo) with: ``` visudo ``` And then add this line: ``` patcy ALL=(ALL) NOPASSWD: ALL ``` to the appropriate place. Please google on what th

Never ever ever do that. Just do ```Future.value(mock[Object])```

You can just mock it twice: ``` mock(favor).test(1) { true } mock(favor).test(1) { false } ``` The first time it is invoked it will return true, and the second time it will return false. It is supe

The first lesson: __You cannot depend on an external module__ There will be discrepancies. Well, you'd better take their modules and modify it to suit your needs. __Pack your own local modules__

This is to test if a directory exists. We can use it with file as well

``` [email protected]:~/Project/readdaily-puppet (master)$ puppet module install --modulepath=./modules puppetlabs-postgresql Notice: Preparing to install into /Users/tanin/Project/readdaily-puppet/module

I have encountered the duplicate declaration problem in Puppet. Here are the things that I learn: __A module (the module path) already exists. You can use them__ This means that, if you want to use

So, I generated a new SSH pair from my laptop. Then, I uploaded the public key to the file ```authorized_keys```. The first time I have to ssh with the private key file with ```ssh -i private_key ta

``` profile.count(any) returns Future.Nil thenReturn Future.Nil ``` It's that simple

Let's say you have a method's signature that looks like this: ``` def select[A](query: String, params: Any*)(f: ResultSet => A): Future[Seq[A]] ``` When you would like to verify it with a mix of ```

Use this: ``` stub.instance_of(Test).use? { true } ```

Let's say we store a tree in a MySQL table with the columns: id, name, and parent_id We use left join to get all ancestors of it. For example, we know that the max height is 4, so we join 4 times. He

I was stuck at IO redirection. It didn't seem to work. At the end, I have found that '2 >&1' must follow '>test.log'...

Let's say you have a method ``` def test(t: String, a: Any*) { } ``` Then you invoke it with: ``` val args = Seq(1, "b") test("aaa", args:_*) ``` When you want to verify with Mockito, you have to

It seems we cannot use ```CSVLoader```, but we need to use ```CSVExcelStorage```. Here is an example: ``` data = LOAD 'something.csv' USING org.apache.pig.piggybank.storage.CSVExcelStorage()

I got ```InvalidUseOfMatchersException```, even I already use a matcher in every argument. It turns out that the method has 3 arguments; the last one has a default value. Next time, when you want to

`stub()` is for replacing the method implementation `mock().a_method.with_any_args` is for replacing the method implementation AND expecting the method to be called once; You may use `mock().twice` i

In ActiveRecord, you cannot invoke ```update_attributes``` on an attribute if you don't declare it with ```attr_accessible```. I was stuck with this problem for about an hour. It was discovered becau

This is because ```Some(null)``` is not ```None```, but ```Option(null)``` is ```None```. So, don't use Some... or everyone already knows that.... Another thing is ```null.asInstanceOf[Long]``` is

If you get this error message: ``` org.mockito.exceptions.base.MockitoException: Checked exception is invalid for this method! Invalid: java.lang.Exception ``` It means that we try to stub

It's always annoying that, when you want to require some file, you have to: ```ruby require File.expand_path('../../something', __FILE__) ``` And if ```something.rb``` requires something else in its

* Thrift IDL is compiled in order. Therefore, you cannot have struct A that uses struct B, but A is above B. You cannot do that * When defining exceptions thrown from a method, you have to name it dif

I was trying to find away to elegant check/uncheck a checkbox in Mustache within Haml. And I think I have found an elegant solution. Here it is: ``` %input{ :type => "checkbox", ('{{#tax_deductible}}

Capybara's documentation doesn't explain well. Here is the method ```select```: ``` - (Object) select(value, options = {}) ``` and here is the description: ``` Find a select box on the page and s

I am in a situation, where overidding ```==``` produces a beautiful structure. But I'm not gonna explain it here. I've run some experiments to verify that what I do will work. Here is the snippet: `

I will separate it into an independent gem later, but here is how I log all the database queries and log the summary usage per request. Rails has a built-in mechanism for instrumenting the things tha

Ok, I'm going to try a new challenge. I will stop complaining for 30 days. Complaining is saying anything negatively without offering a solution. For example, I cannot say "I hate that it is raining

Rails' logging has annoyed me for a very long time. Since I am not around to monitor GIVE anymore, I've decided that I'm gonna make logging more comprehensible, so that I can diagnose what has been go

[Rails' footnote](http://github.com/josevalim/rails-footnotes) is sooo cool. It adds a bunch of debugging information at the end of every HTML page. You can easily debug your page without looking at

Right now I'm planning on the migration from [GIVE.sg](http://www.give.sg) to [GIVEasia.org](http://www.giveasia.org). GIVE.sg is built with [Stripes](http://www.stripes.com). Fortunately, we will on

Today I was walking to a breakfast place.. Suddenly 2 homeless guys came to talk to me. He was very nice; He was telling about a few free dinner place that I could go and also about which area was ni

Today I have encountered a very weird bug. The symptom is that a Model cannot be saved, but ```model.errors``` contains nothing. It took me like an hour to figure out the real cause. It turns out t

We can just get a diff: ``` git diff > patchfile ``` And we can apply it on any branch: ``` patch -p1 < patchfile ```

I've encountered a weird situation where I need to deploy 5 branches at the same time. I have to check for conflicts between branches, otherwise the conflict pair will be rejected from the deployment.

It is fairly simple. First of all, you must define the new element's type with this hook ```hook_element_info()```. For example: ```php function something_element_info() { return array( "mult

So, I have been building a Drupal module. I've learned a lot about its architecture. But, there is one pain from building a module: * when enabled, your module needs to install a database schema * y

For some reason, my local master branch is reported to be ahead of the remote master branch, even though I never modify the local master branch. Katsuya told me it was because the local master branch

But a UTF-8 encoded string doesn't contain it. Today I loaded a file containing a UTF-8-encoded string, and tried to parse it with CSV. I couldn't really succeed, even I saw that there was nothing w

I am reading the book "The power of habits". It gets me to think about the habits that I've changed. I think the first extremely bad habit that I've eliminated is biting nails. I've been trying to th

Oh yeah... I've read it. I was not a big fan of LDR. When I moved to another country, I always stopped a relationship. My attitude was that LDR sucks and is torturing. Back to the book, it simply pr

Try resetting its cache with ```module_implements('webform_component_info', FALSE, TRUE);```. And here is my code: ``` function multilevel_webform_component_info() { return array( 'multi

There is no hook, internally. There is one hook ```hook_webform_component_presave()```, but it is for other modules... It's like WTF?!? ------------------- I was wrong. It's just that you have to

__Remark:__ This is a clumsy way to add a component, as the component is integrated into WebForm's source. You can actually build an independent module that utitlizes WebForm's hooks in order to build

I've evolved my reading list so far that right now I'm reading about relationships, instead of business, programming or some other shits. I vividly remember a friend suggested that I should start rea

TBD

Do not use the number of characters as the header.. but use the number of bytes..

I've been fighting with Bonjour for a day now. Finally, I've figured it out somehow that Bonjour cannot be run in a thread, that ends. If you do that, you have to tell Bonjour to run itself in the ma

Please use: ``` NSString *dataStr = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease]; ``` DO NOT use: ``` [NSString stringWithUTF8String:[data bytes]] ``` It return

Today I tried to put everything in *.h in Objective-C. I put the ```@interface``` and ```@implementation``` in only one .h. I don't know why this happens, but XCode will throw out a very weird error

So... let's say you have ``` NSMutableArray *test = nil; ``` And, then, you forget to initialize it. This is one of the weirdest behaviour that I've encountered. You can call ```[NSMutableArray ad

After figuring out for a while, ```Capistrano``` is still the best one to deploy any app to a production server. Let's do some quick overview; Here is what ```Capistrano``` does: 1. Login through SS

Yesterday, I have found a very weird bug, which causes an irregular behaviour. I won't explain it here, but here is the problem: Let's say I have an array: ```array = ["a","b","c"];``` Then, I woul

This is a 2-day hackathon to build an online multiplayer card-game __Jubmoo__, which is very similar to Bridge. Right now I'm designing the server, which is Node.js + Redis. I'm using __Node.js__ be

This is for solving the problem "Too many links" in Linux. You know that you cannot have more than 32,000 files in a single folder. (Increasing the inode limit is also not a good choice.) So, this i

This is Nginx config for Ruby on Rails: ``` user deploy; worker_processes 2; #error_log logs/error.log; #error_log logs/error.log notice; #error_log logs/error.log info; #pid logs/ngi

It's not focus; it's patience. I'm reviving 2 of the old products and will let them run for some months.

You can force ActionMailer to write an email into a file by: * In your environment file, add ```config.action_mailer.delivery_method = :file```. * Or at anywhere, add ```ActionMailer::Base.delivery_

This is the second time I've gone to a church. I won't talk about beliefs and things like that here. What I'm really impressed is the management behind a church. Few rituals, that I have noticed, ma

I don't know whether to laugh or cry... If you assign the SMTP setting like this: ``` ActionMailer::Base.smtp_settings = { "address" => "smtp.gmail.com", "port" => "587", "authentication" => "

I read this 2 months ago as well. It's a little bit outdated, but the principles are amazing. This is a must.

I've bought this book for like 3 years and bought it again on Kindle a year ago, but I never did read it until last monday, in which I decide to read the physical book... It's a popular economics boo

These 3 months I have read 3 more books: Out of Characters, How to instantly connect with everyone, and The fine art of small talk. Well, they don't really help. The one that is interesting is Out o

This is a book about the technology and the engineering discipline at GIVE. As I will move to Twitter very soon (on Oct 2012; right now it is Aug 2012), I need to pass all of my technical knowledge to

Today I have (almost) finished the new layout of GIVEAsia, and I've made it compatible with IE 7,8, and 9. The features of GIVEAsia seem to be crystalized, though we plan to make them richer. I real

IE7 doesn't support display:inline-block -------------------------------------------- That's very easy to fix. For every ```display:inline-block```, append ```zoom:1``` and ```display:inline```. Or

I've tried many ways: * Wine that comes with a fake IE, but it's a fake one * Trying to install IE6 with Wine, but it doesn't work because of the fucking fake IE is there * Trying VirtualBox, which r

I've been using this library for a year. It serves me well. Maybe it might benefit you, too. Here is the trivial problem, when you are build a webpage: When a user clicks on a submit button in

Another FTW facts... My Rails project totally collapses. On the development, there are like 50 CSS files, but those CSS files are combined into 1 file in production. FTW, man.... Here is the quick

I've noticed that after I finished the 4-hour workweek, I was very productive for a month. I think I want to theorize that, by reading a productivity book, it will boost my productivity for a period

___The recognition of pain and fear in others give rise in us to pity, and in our pity is our humanity, our redemption___ It is indeed my great redemption :)

Yup, I've just checked the water level at [Thaiwater.net](http://www.thaiwater.net/DATA/REPORT/php/egat_dam.php). You can easily compare today and today in the previous year. The water level in the

My friend downloaded Wubi.exe from the Ubuntu website, then installed it normally. It turns out that Wubi installed the 64-bit version of Ubuntu into her laptop, while her laptop has 32-bit CPU. WTF

Normally, I'm using 3 branches, which are ```stable```, ```staging```, and ```master```. When you want to make a big change, please branch from ```staging``` by: 1. ```git checkout staging``` in ord

Now I know why people don't build an RTMP server in order to record a video from a Flash client. The number on reason is that the quality might be bad and we have NO control over it. After a week and

It is very difficult to build an RTMP server. The most difficult part is that the RTMP document is very misleading. For example, Message is not used at all. CommandMessage doesn't follow the format

Today, I got stuck at a problem, where a Flash client requests "createStream", then the server has to reply something. The document says: ``` NetConnection is the default communication channel, whic

Today, I have finished the serializer/deserializer of AMF0. AMF0 is a language use in CommandMessage of RTMP protocol. At first, I thought that I'd have to implement AMF3 serializer. But I've found t

Assigning 8 bytes into a double variable ------------------------------------------ ``` int amf0_deserialize_number(double *number, unsigned char *input) { int i; for (i=0;i<8;i++) { memcpy((

I just finished like 80% of the AMF0 serializer/deserializer. Tomorrow, I'll work on serialize/deserialize an array. And on a higher layer, I have built the InvokeMessage serializer. Tomorrow, I'll

I've found out that building an RTMP FLV-recording server involved 3 specifications: RTMP, AMF0, and FLV. Right now I am at the half way of finishing RTMP, but I have found out that I have to finish

Not that implementing RTMP is difficult, but its document is poorly written. I have encountered 2 examples: The first one is the default size of a chunk. I've discovered that it is 128 bytes. Should

Today, I was trying to build an echo server with C. I have gone through so many things. Configuring Makefile is the first hurdle. It took me like 2 hours to make it work correctly. Setting the testi

Well, it's not that C is weird; it's just tough in general. Today, I'm trying to implement a high-performance echo server. I've read a lot of stuffs on the internet and found that using __libevent__

I wanted to read it like a week ago. I haven't finished it yet, and I only read like 10 pages of it... I will finish it tomorrow..

~ So on this very special day I would like to say to you I hope you'll always find happiness In whatever you may do. ~

GIVEAsia is almost complete, in terms of functionality. Tomorrow, I think I'll start adding test cases for all micro-actions. We currently have 600+ registered members now. The re-designing of UI wil

On 31st July 2012, I have a presentation on whowish_word. It is a WYSIWYG version of i18n. Here is the presentation: [Presentation](http://tanin.nanakorn.com/slide/whowish_word) What I want to get f

If you have a model that subclasses another model, and the superclass defines a carrierwave field, you have to redefine that field in the subclass. Otherwise, you would encounter a very weird, interm

Today I've made a lot of minor changes: moving things around and adding search filters (country, micro-action). Tomorrow, I'll work on: Donate anonymously, and hint box at every page. For the RTMP S

These past 7 days I have been making some changes to the architecture of the websites. Right now the architecture is complicated, and there are many push architectures. I begin to realize how to man

I've decided that I'm going to build __a flash recording-video server__. I've been scouting around, and there is no good solution, not even Red5. I think I'll go with Ruby/EventMachine, and if it's

Today I tried 2 Flash Media Server and tried to record video through Flash. The first one is Red5. It's built on Java... Oh man, I hate Java XML configuration for a web server. I can't seem to get it

I kind of skip like 10 days... because I was in Thailand. My routine didn't work in Thailand, and I was super distracted by, of course, girls. (There cannot be any other reason why I'm so fucked up)

I somehow believe with many people telling me this: My next big challenge in life is ___the complete focus___. I'll get that within these 60 days.

It was a good conversation today with Yuki. After that, with my depressing artistic talent :P, I've sent her an sms. ``` It was fun hanging out with you; I know deeply inside you feel it too. Now I

Today I was flying back to Thailand... I don't know why I have fear every time I fly. I'm really scared that the plane will crash. Man, I still have to fly, at least, 5 times before arriving San Fra

Finally, today Paypal and mPayment work on GIVEAsia.org. There were several tricky problems. I think, on Monday, I'll start optimizing the website. At least, all the (N+1)-quiries problems should b

Today, I've got a newsletter from PEOI.org. Well, I get a newsletter from them like once a week for the last 6 years. I did apply there as a volunteer 6 years ago, but I never did anything for them.

In RSpec, I have found out that the model is defined twice. And if you use ```after_create { |record| ... }```, then it will be executed twice...

Do you know, when you create indexes, Mongoid doesn't remove undefined indexes? That is annoying and causes me a problem. So, here is the rake task for removing all indexes and recreating only the o

Today I cut images for the iPhone app with Photoshop. Man, it looks beautiful. And today I finally got the girl's name. I was super smooth. I was like "you know? I'm coming here to change the world

Today I met with Henry. It was a really good talk. I do hope we all can pull off this iPhone app stuff. It's one of the greatest idea I've ever heard. Tomorrow, I will work on the Photoshop stuff. Y

I have finished the basic version of GIVEAsia and deployed it already. And then I also finished the book "The Fine Art of Small Talk". It's very eye-opening for me. I am in many ways a conversation k

Today I finished the iPhone app. It works perfectly. Tomorrow, I'll move the staging site to the production site. I'll also work with Henry. He'll do 2 webpages.

I always forgot that fact....

Today, I spent 5 hours, making a lot of changes to GIVEAsia. Super tired... Tomorrow, I'll start working on an iPhone app again.

I blog this as a reference. Backup: ``` ./mongodump --db [dbname] --out [some_dir] ``` Restore: ``` ./mongorestore --db [dbname] --drop [the_backup_dir] ```

Today I spent like 4 hours to finish a lot of stuffs. It's only 4 hours, but I feel I achieve so much... I don't know why. We have a parent-child movement. The donation works beautifully. Tomorrow,

Today, I spent like 4 hours to build a member system and a donation mechanism. I wanted to achieve the challenge, in which I asked for a girl's name. So, today, at the Starbucks in NUS, the girl, wh

Today, I expanded the harddisk of GIVEAsia's server on EC2. Can you believe that our server had only 8GB of harddisk before? I added a 100GB EBS to it. We won't need to touch it for a long long time

First of all, create a new EBS and attach it to your instance through the AWS website. Now login through SSH and type: ``` cat /proc/partitions ``` This is to check whether or not your instance see

I didn't really do anything today. I improved the UI of whowish_word a little. I also attended the hackathon event in NUS. It was so full of energy. I should have joined the event. I only sat in on t

I am sick today. I spent like 2 hours to redesign the website and shit. Then, I was so dizzy that I couldn't work anymore. I watched like 10 episodes of The Big Bang theory, which, in turn, made me

I spent like 5 hours in order to build an iPhone app. Well, actually, I spent 1 hour in order to make a custom camera, renew the developer certificate, and other shits. Anyway, the iPhone app is wor

Today, I spent about 4 hours in order to build the prototype of a new idea, which involves an iPhone app. I spent like 2 hours building the backend and the website part, and another 2 hour to setup x

Today, I built 3 importers from 3 sites, fixed whowish_word bugs, and deployed (and test) the website. I spent in total 4:45 hours today. I feel pretty good. And I've requested to talk at the next

Today, I spent like 3:30 hours in order to setup the whowish_word's demo site and build the importer stuff. I was highly distracted by the news and shit. And today I also went to a Ruby meetup. Lif

Now that I have your attention. It's not really the technology of the decade. whowish_word turns every static string on your Rails' site into an editable one. Please see the demo here: [whowish-word

Today I spent like 5:30 hours in order to build the charity stuff and improve WhowishWord. WhowishWord, I believe, is one of the technology that can change the way people work. I've made it database

Today I have added another micro action, which is yes/no, fixed Facebook publishing, and fixed other shits. I spent only 3 hours today... I had a dinner with friends today at Clark Quay. Clark Quay

Today my focus was very intact. I spent like 5 hours. I feel I achieve many stuffs. I don't really have any complaint today. In a normal day, I'll work at the Starbucks in Yusoff Ishak for like 2-3

Today I spent like 4 hours. I got stuck on FB publishing problem for like 2 hours. It was super annoying. Then, for another 2 hours, I have designed the activity feed and completed the detail. The

The Facebook documentation tells me to use HTTP Post, but the parameters should be sent as a query string. I thought I could send parameters as POST's parameters, you know, in the HTTP body. It turn

I almost finished the site (again). The things missing are: * Activity feed * Facebook Open Graph stuffs I think I'll finish these 2 things within 2 hours. And I think I'll design the basic system

Today I have spent roughly 5:30 hours. It was not bad. I have achieved many shits. The new website is almost complete. I think I'll complete it by tomorrow's night. I felt tired at the end of the d

I've just spent 1 hour to make the searching feature on Giviki. I was lost for like half an hour because, at first, I was doing the browsing feature. Browsing doesn't make sense. Why would users bro

Let the journey begin. Even if I have to die at the end, I'm finishing this product. This is the day number 1. Today, I have spent 1.30 hours in order to: * Donate through Paypal and track the don

We've agreed to do 100-days (roughly) marathon at GIVE.sg. Long-term productivity is a hard problem. I'll try to reach 6 hours a day without interruption, at first. I think I will need to time the

Ok, I've admitted it. I am probably the only one who said I was a volunteer for GIVE.sg. I have tried many terms: Volunteering Engineer, Engineering Volunteer, and Software Engineer. (Yeah, even Soft

Today, I have been preparing my speech for the Twitter event. You can see the detail [here](http://tanin.nanakorn.com/twitter.html). I've just realized something that the FB recruiter did. And it was

Ignore all StackOverflow's posts. They don't work. Follow this instruction: [Devise-Async](https://github.com/plataformatec/devise/wiki/How-To:-Send-devise-emails-in-background-%28Resque,-Sidekiq-an

Today, I got stuck because I couldn't connect to the Paypal's sandbox. I was using Ruby's standard https library. I could connect to ```https://www.google.com``` and ```https://svcs.paypal.com```, b

I've installed RVM on Ubuntu like 5 times. Every time the gem's path is wrong. I've found this [post on StackOverflow](http://stackoverflow.com/questions/8990828/rvm-bundle-install-missing-gem-error-

Human is amazing at associating our senses holistically. I still remember the feelings when I was in Singapore 10 years ago. The flush of the feeling comes back every time I hear the songs, The Last

I'll write more about it. It's true in so many ways. One of the main reason is that: *When you build a thing, you'll learn many new stuffs. So, it's easier to change it later in time, simply becaus

I still procrastinate some tasks from GIVE.sg. I am supposed to finish re-designing pages to make it more usable. I procrastinate by doing some other tasks instead. This is the most insidious way to

Normally, when I want to achieve something, e.g. reading one book a day, I will publicly announce it on Twitter, FB, and my blog. This is a great trick to avoid Procrastination. When you have a milli

The book is very inspiring. I think I am heading toward Linchpin whether or not I read this book. I am already half way there. I am already serious about my art and my craft. I am emotional about m

*Blessed are those who can give without remembering, and take without forgetting.* The quote is from Princess Elizabeth. I shall live by this quote.

If you use a string ```id``` in Mongoid, then when the searching with Solr won't work properly. When you try to obtain the results, Solr will throw an error ```sunspot BSON::InvalidObjectId (illegal

Ok,let's try a new plan: * Divide a big task into one-hour tasks. Time it! * I shall test/debug after finishing the code of an one-hour task. * Take a 15-minute rest between 2 tasks And here is the

I've been playing around with Titanium SDK for some days now. It's an ok platform. I've figured a way to organize files into controllers and views. It's still not complete. I want to find the way to

This is a difficult book to read. The book uses complicated and abstract terms. For example, * The timeless Being * Unmanifested * We should put our attention on our Unmanifesto or Presence. It cit

Here is the rule of thumb: *The task should be as big as possible that you can code the whole task without producing errors and without testing.* If a task takes you 30 minutes and you later discove

I test too often. I have to eliminate this impulse. I seem to test every 10-15 minutes. It becomes a bottleneck when the testing takes too long, for example, starting an iPhone app. New goal: Test o

I've just finished the book "Founders at Work" today. I didn't really have time for the last 2 weeks. I need to be a little bit more disciplined, I guess. The last 2 weeks, I need to finish some feat

ERP stands for Extremely Rapid Prototyping. Today, I almost finish my third project. So, I think I should write about the 3 projects I have done for the last 3 weeks. Squeks.com ------------------

Even my image's size is 1936x2592, it writes to 3872x5184. And I don't know why... The image is generated from a graphic context. Everything should have been fine. Anyway, I resize the image from 19

I needed a simple UITableView, which scrolls horizontally. So, I just built one. It supports: * clicking on a cell * customizing cell But: * All cells must have the same width * It doesn't reuse

I am building a custom camera, and what I have noticed is that the capture image from the video output is not as sharp as the one in the ```AVCaptureVideoPreviewLayer```. The difference is almost un

Now this is what I call stupidity.... When I need to assign an object to ```@property``` in iOS, I figured out that I should make the code shorter. So, what I did is this: ``` self.camera = [[GLCame

Never ever set the image of ```UIImageView``` before it is shown. Otherwise the image wouldn't show.

First of all, install ```tomcat```. You can choose your own version. ``` yum install tomcat7 ``` Now we need to install Solr manually. Let's first download it: ``` wget http://mirrors.issp.co.th/ap

It is indeed a roller-coaster ride, especially when one wants to use it with Mongoid. Here are things I have to change to make it works: 1. Mongoid doesn't support ```find_in_batches```. So, I have

I have decided that I'm going to launch something, a new product or a new version of a previous product every week. I've figured out that nobody really tries to ship 20 products within 6 months befo

Ok, so here is the script for scaling a server. ``` sysctl -w net.core.somaxconn=40000 sysctl -w net.core.netdev_max_backlog=40000 ulimit -n 100000 ``` And edit the open-file-limit for the user who

*This works with Amazon EC2 with its original OS* Here is the steps: 1. Uninstall Ruby 1.8.7 2. Uninstall Rubygems 3. Install Ruby 1.9.3 4. Make a link from ruby1.9 to ruby 5. Install Rubygems for R

Here is the problem for tonight: ``` A set S contains 0 and 1, and the mean of every finite non-empty subset of S. Prove that S contains all the rational numbers in the unit interval. ``` Ok.... L

I've just built a PHP Database Migration Library in order to manage changes in the database's structure, for example, adding columns. It generates a unique identifier for each migration script, there

I'm working on SWF hacking in order to build a seamless licensing for a SWF (Flash) application. Here is what I have found so far: 1. Always reading in bytes. If the specification said that it uses

*Works only on Amazon EC2 with Red Hat Linux* It starts getting annoying when I have to deploy like 3 Ruby-on-Rails apps. I'll build a script to ease the process. Here is the rough outline of all t

I must ship something every week in order to guarantee that I, at least, create something!

You cannot override an instance variable of Struct. It's weird. Observe: ```ruby class UpdateFriendVoteJob < Struct.new(:member_id, :question_ids, :force) def perform puts "#{question_ids}"

The problem sounds familiar. I might already solved it. But that doesn't matter. I'll try to solve it again. Here is the problem statement: ``` Given 25 different positive numbers, prove that you ca

This is a very very good book, even though the introduction is a little bit bogus and pretentious. It sounds like the work-at-home advertisement in Thailand. Anyway, the philosophy presented in the b

As a reference, this is [the right way to configure SSH connection](http://articles.slicehost.com/2009/5/13/capistrano-series-setting-up-git).

I thought I would practice Google CodeJam on 22dn of March. Today is 27th of March already. Gosh, I'm so dead. Anyway, here is the today's problem: Problem Statement -------------------- Let ```n``

When you are in this kind of situations, where there are many clients and one server. The clients generate data models, store them locally, and submit them to a server. Let the client generate unique

Somehow today I have come to a realization how big the privilege I have. Sometimes I just want what I want too much that I forget about how lucky and privileged I am. My first achievement in my life

Today I have found out that: If I don't initialize NSMutableArray and use it, there will be no compilation error. But a new element won't be added. What an annoying problem...

This is the second time of my reading day; I'll try to finish one book within one day every week. Today I have finished the book "Predictably Irrational". Well, actually I have finished 2/3 of it bec

I did ```bundle install``` and it still threw an error that it couldn't find other gems. What the fuck was happening? I cannot solve this problem. A workaround is to install gems in a relative path

I have encountered a very annoying problem. I want to use Ruby on Ubuntu. So, I installed RVM and shit. Now I found out that all gems' executables didn't work. It threw an error like this one: ```

Last Saturday, I have finished the book called "The Luck Factor". By the way, I declare Saturday to be my reading day. I shall finish one book on that day. The first half of it iterates all the beli

I want a grid view to show a list of thumbnails. The grid view should allow me to specify the number of columns and the size of a cell. I googled around for a while and found a few of them. They are

```whowish_word``` is one of my greatest invention. Normally, on Rails, you would have to edit a locale YAML in order to change static strings on your site. ```whowish_word``` enables you to edit a

```EXC_BAD_ACCESS``` might mean many things. Normally, it means that you release an auto-released object, release too many times, or use a released object. Here is the way to debug it. First of all

See this example: ```objc // In the init function UIView *v = [[UIView alloc] init]; [self addSubview:v]; _someVar = v [v release]; // In the dealloc function [_someVar release]; _someVar = nil; ``

This is because ```%@``` must be used for a pointer-alike variable. For a primitive-alike variable, we must use a correct symbol, for example, ```%f``` for float.

Today I have found out that ``` if (!NO) { ... } ``` is not working as I expect... ```!NO``` is not a true statement.

This is because ```DISPATCH_QUEUE_PRIORITY_BACKGROUND``` does not exist in iOS 4.2 and earlier. Please use ```DISPATCH_QUEUE_PRIORITY_LOW```.

``` warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1 (8C148)/Symbols/Developer/usr/lib/libXcodeDebuggerSupport.dylib (file not found). ``` If you found t

Today I have succeeded at streaming video from camera and showing it on the screen. Also, I have succeeded at manipulating pixels before showing it. The normal way is to: 1. Write your own ```AVCapt

Simply do not forget to add the files to "Copy Bundle Resources" (under the project configuration)

* There is no type-casting. Use constructor. * When declaring float or vec, you must declare its precision, otherwise there would be a compile-time error. * You cannot multiply float with integer beca

This year, Google CodeJam Qualification Round is on 12th April 2012. Last year, there were 30,000 participants. I have ended up at the rank 895th. I didn't train very well last time, and I didn't un

Here is one annoying problem. In iOS 4, when I want to dismiss a modal view, I would: ```objc [self.parentViewController dismissModalViewControllerAnimated:YES]; ``` But that doesn't work on iOS 5

I have decided to re-innovate my website before practicing for Google CodeJam. Yes, it is a very weird prerequisite. I have been frustrated with poor blog engines. I have been using Blogspot.com for

Yesterday I was trying to find a way to create multiple-column UITableView. Surprisingly, this is not easy to do. Some posts on StackOverflow suggest that we build it out of UITableView. That is w

900K tablets will be bought by Thai government and distributed to 10-years-old kids. Everybody in Thailand keep arguing about whether or not this policy will pay off. ___Well, I don't care about

I am so tired. I woke up very excited every morning for 2 months (evening in SF == morning in Bangkok) checking my e-mails. Sometimes I was rejected and sometimes I was accepted to a next round. I'

Alright, the first version of my preparation is not concrete enough. It is not focused enough. So, I come up with a new plan. I have done a scorecard of outcomes and competencies. (It might be a li

Expensify's Interview Preparation ================================== Expensify is a very small company. Normally, within a small packed group of people, its culture should be unique and somewhat stra

Conceptual questions ====================== The only area that I never practice on is the design questions. Here is the raw list of some of the questions: *Architectural questions* - How would you

Onsite Interviews ========================== I finally get onsite interviews with Expensify, Facebook, and Twitter. These last 2 months are not really a superb experience for me. It was like a rolle

Squeks.com ======================== Squeks.com was born around 6 months ago. It's just a website where you can click 'love' or 'hate' public figures. What was happening with it is that it got so pop

Interview phase is coming to an end ================================= I am so tired and have been excited waiting for a result after each interview. Too much excitement makes me feel tired. Right no

Causes.com's rejection ========================= Ahhh... I feel super depressed. I really have no idea what went wrong. I finished the given task, though it was uncomfortable because I am a Windows

Startups are super interesting =============================== They have solid goals and extreme passions. Even an HR guy sounds passionate. My first impression with every company that I have talked

Scribd rejects me ===================== They reject me without any interview. I don't know why... I would like to think that it is because of the visa stuffs. But that is unlikely to be true. I thi

Job Finding Madness ===================== I have so far sent a resume to: * Google * SpeakerText * Posterous * Thoughtbot * HealthTap (In Process, Quiet) * Facebook (Rejected after onsite) * Twitter

Zombie Syndrome ======================= Today I would like to write about the zombie syndrome. The idea has been thrown around for a long time, I believe. I have found the explanation of this syndrom

Min and Max =================== Given an array, find Min and Max with the least comparison. Now the classic way to do is to loop. That's *2n* comparisons on the worse case. The best case is usin

2SUM problem ====================== Given an array a[0] ... a[n-1], find 2 elements that sum up to k Now this is a classic problem. Everybody will certainly say it is O(n^2). It turns out that

Facebook Interview Questions ============================ Right now I'm preparing for a phone interview from Facebook. I have done all questions from [XORSwap](http://xorswap.com/companies/5-faceboo

Empowerment ======================= I believe Empowerment is the key to produce quality work. Currently, I have applied two empowerments: The first one is using WhowishWord. It allows other people,

N independent decisions ================================================ About 5 days ago, I have an phone interview with a Twitter engineer. He asked me to: Given a string, for example, aa-(1,2

Problem Solving Dichotomy =================================== I do believe that given a problem, *You either solve it or you don't* If you don't, you need to seek for a solution elsewhere. It's pr

Foodling - Find the dish ========================== Somehow I do feel that my team has grown up by some extent. At least, we know how to draft a sounding mission statement. After we built Gamling.or

A long array A[] is given to you. There is a sliding window of size w which is moving from the very left of the array to the very right. You can only see the w numbers in the win

It's using the same old technique. I'm bored. Let future Tanin solve it.

Given 2 sorted arrays, n and m in length, find the median. First, let's just assume that the numbers are unique and `(n+m)` is odd. The first obvious solution that comes to me takes `O(n)`.

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for “abcabcbb” is “abc”, which the le

Given an array A of integers, find the maximum of j-i subjected to the constraint of A[i] < A[j]. This is a really really good interview question. I love this kind of questions. It is

It's so difficult to find a general manager to run a website. I have finished [Baanling.com](http://www.baanling.com) for weeks now. Still, I cannot find anyone to take over and run the website.

Given an integer of n bits, reverse the bits. I am not very creative in solving a problem. Of course, everyone, including me, can come up with O(n) solution. The real rock-star will come up

Implement a function that matches a string to a regular expression. The regular expression only contains a-z,'.', and '*'. * matches any string that precedes it, even an empty string

Given a string s, find the longest palindromic subsequence A subsequence of string is the string with some characters removed. For example, aaa is a subsequence of bcabcabca. First of all, l

Given a string S, find the longest palindrome substring. A palindrome string is a string and its reverse are the same. my dynamic programming skill is still ok. First of all, we can immed

Tonight I'll work on the webboard of EcoHealth. God, I should have known that I should not take any consultant job. Now it's biting me in the ass.

I don't know why I have an attitude that I should try to solve problems on my own even if I already spent an hour on it. I think it is a wrong attitude. When I study language and I don't know so

I should have realized this for a long time that my style of working is very different. Anything that I have felt success usually goes like this: 1. I declare a ridiculously-early deadline (a few d

There are so many techniques in Mathematics that I am not aware of. Here is another problem, which I didn't even know how to begin to solve. Prove that every set of ten distinct numbers between 1

Given a sequence of n numbers, a[1] a[2] ... a[n] Replace a[i] with |a[i] - a[i+1]| (if i == n, then with |a[n]-a[1]|) Repeat it until every element is 0. Prove that with n=5, it may g

Given an integer n > 1, the sum of 1 / (pq) for all p,q that 0 < p < q <= n and p + q > n and p,q is relatively prime is equal to 1/2 The first thing to notice is that we have t

Given 25 different numbers, prove that you can pick 2 numbers that their sum and difference do not equal any other numbers. We should first address the problem formally: Let a[1] < a[2

This is a problem posed by my girlfriend's boss at NovaLeaf. The problem is: Given n brackets, how many are the combination of valid brackets? For example, 2 brackets have [][] and [[]]

It is just amazing that I've just realized this. This week I enable my friend, a designer, to make changes to the website directly. He has to learn the structure of Rails 3.0. But it's merely views

Tonight I'm doing the very first hackathon. I'm building a platform to connect the ones who offer rental rooms/houses and the ones who want to find rental rooms/houses. The website is extremely

I've found out that I am usually 100 times more productive when I decide to write a program within one day. It's surely tiring, but rewarding at the same time. Right now what I really need is to pe

There are 100 lockers in a room. The 1st student opens every locker. The 2nd student closes the lockers whose number is divided by 2. The 3rd student toggles the lockers whose number is divided

There is a NxN board. Alice starts first by marking a cell. Next, Bob must marks a cell that is adjacent to the previous cell. Each player takes turn. If someone cannot mark a cell anymore, the

If small rectangles, each of whose either width or height is integer, compose a big rectangle, then the big one has either integer width or height. Prove that. This problem is just really rea

Around 6 years ago, I didn't believe in speed reading. Still, I bought a book about speed reading anyway. I didn't really believe in the techniques it offered. I still don't believe them these d

There are an even number of coins arranged in a straight line. You and your friend may only take coins from either ends. You and your friend take turn to take one coin at a time until there are

What I have found during the years is the problem so called "Delusional Boundary". I am almost always wrong at a judgement call at something. Gamling.org's delusional working hours -----------

As running fast required in Sport, reading fast requires some basic skills. This is not to improve understanding while reading but to train our minds to consume information faster and longer. Th

There is a billiard ball on a square table (with no holes). Find angles in which the ball is shot and travel in a cyclic manner. This simply means that at some point of time in the future the

I believe so. Nowsaday, with the Test-Driven-Development(TDD) approach, I feel painlessly already. This journey is about what components I have found and used to facilitate software development or

The reading skill is so fundamental to your learning rate. Almost anything you learn involves reading. So, the faster you read, the faster you can learn. Even though it is composed of 2 set of skill

I have been coding for years now. I have found out that a great programmer should acquire these 3 skills: * Translate a concept into code * Write beautiful code, minimizing redundancy and maximizi