Context and disclaimer: I run an intense and successful bootcamp focused on preparing for Tech interviews. A 100+ people from all over the world have prepped with us since we started a year and a half ago.
http://interviewkickstart.com.
We've since learnt a lot about what makes successful engineers. While nearly everyone who goes thru us (and is actively looking) gets placed somewhere nice, the people who crack some of the hardest interviews generally fall into ONE or MORE of the following categories:
1. They are just bright from the get go. A high IQ.
Haseeb, from the little I've read about him, seems to fall into this category. They can get by with normal amount of practice viz. brush-up.
2. They are extremely prepped.
A crude measure of prep, is how many algorithmic problems you've practiced. Some of these people have crossed 300+ problems. Written code for each. And repeated it. It takes several months to a year to do this with diligence and focus.
3. They have been coding for a long time. Almost precocious-ly.
They have written so much code, that a lot of constructs are now muscle memory. All they need to do in an interview, is to intuit the solution. After that, they impress the heck with their coding fluency.
4. They are competitive programmers for some time
They don't have to be toppers or winning competitions. e.g. Yellow on Topcoder is sufficient.
5. They went to a particularly strong and competitive CS program
Some programs in the country prepare you for such interviews. Rare, and difficult to get into, but they do.
6. They got a soft interview-panel.
Interviews are heavily dependent on who interviews you. Especially at large companies, there is a wide variance in grading standard, experience in interviewing and beliefs, and hence there is a wide variation in talent, despite centralized hiring committees.
You need a bit of luck anyway, but sometimes you get an entire panel that you happen to gel with. A little bit of preparation and getting such a panel puts you over the magic line.