Thomas Lextrait

Sr. iOS Developer at Google

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Meeting Knuth

I met Don Knuth in 2007 when I was 17. He owed me $2.56 and I wanted to trade my finding for the check in person, with the hope that I could shake his hand and maybe get a couple books signed.


Dr. Donald Knuth is a famous Computer Scientist and professor at Stanford University. He is most well-known for writing The Art of Computer Programming, as well as implementing TeX.

Dr. Knuth has written a lot of software and would usually reward people for finding bugs in his programs. The reward is one hexadecimal dollar (0x$). Unfortunately $256 is a lot so the reward is actually $2.56. Every time someone finds a new bug, the reward doubles. Don Knuth also rewards people who find mistakes in his books.

I really wanted to get my hex dollar and finding a bug in his programs is no easy task. Finding errors in his books isn’t much easier, especially when your native language is French and...

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Equations with Markdown and Svbtle

Markdown is a very simple markup language that’s quite popular right now, notably it is the one used by Svbtle. Markdown was mostly designed for casual writing, but it turns out that I casually write things in ways that most people don’t.

When I don’t write online I use LaTeX. I use it for everything from homework to recipes. It is a tool designed and implemented by Don Knuth and improved by Leslie Lamport (TeX -> LaTeX). LaTeX allows people to write research papers, books etc. and features a complex and powerful markup language. I like LaTeX very much because it allows me to display math equations beautifully. Unfortunately Markdown doesn’t natively allow users to write math in such a fashion.

I did some research and found out it is possible to integrate LaTeX equations with Markdown, except Svbtle doesn’t provide it. The only solution is to embed an image of the equation into your...

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This weekend I decided to refresh on C++ in preparation for some interviews. I tried to pick a project that I could code in roughly one day. It should not only have me review C++ but force me to solve some problems and implement some data structures I don’t necessarily use every day.


Anagrams allows you to find anagrams in the English dictionary for any given set of characters, then prints them out in alphabetical order, while displaying some stats.



My goal is not to build something that just works, but to actually build a decent solution that’s efficient and lightweight, while exploring a few things. This is neither the quickest to implement nor the most efficient, so please view this post more as a study.


Here are some very basic to average problems that building this program entails:

  • Storing an English language dictionary that the program can read
  • Storing...

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Driving in Japan

Driving in Japan is great and you should do it. So far I’ve driven four times in Japan and discovered new things every time. So before anything, there are some requirements:

  • You must be 18 years old or older
  • You need to hold a valid US, French, British or Swiss driver’s license (Don’t know about other countries but it doesn’t look good)
  • If it is a US or British driver’s license then you need an international driving permit, otherwise you will need a Japanese certified translation of your driver’s license (see links at the bottom)
  • 2 months of planning (trust me on this)
  • A sense of adventure


Obtaining a car

So first off, you need a way to obtain a car. That’s not so hard, you can rent one. You can simply go to your favorite car rental company, let’s say Avis and select Japan in the drop down; surprise: Japan is not there. In Japan, the leading rental companies are actually car...

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