How do you find the missing number in a given integer array of 1 to 100? (solution) [1]
How do you land a job at "startups like Uber and Netflix; big organizations like Amazon, Microsoft, and Google; and service-based companies like Infosys or Luxsoft"?
Easy - by rote memorization. And a healthy sense that it's to best not question the basic idiocy behind cargo-cult interview tactics like these.
Because apparently genuinely useful critical thinking skills -- beyond such trivial matters such as how to get a better space-time tradeoff on that petabyte-scale fibanocci generator[2] our customer desperately needs you to design a viable POC for right now, on the whiteboard, before lunch -- basically aren't needed at these companies.
Notes:
[1] You think I'm just being snarky? It's famously common out in hedgefund-land for people to get hired more or less on the basis of being able to whip out a deadpan response to "gee-whiz" questions like these. And to get "flushed" for their inability to do the same. Startups aren't quite so naively reliant on shibboleth questions of this sort -- but but only slightly so.
[2] I'm being slightly hyperbolic with this example -- but only slightly. I've long since lost count of the number of times been asked "design" questions really only slightly more ridiculous than this example. And as a matter of fact I've been asked an "advanced fibanocci" question -- and apparently received a job offer to a large extent on the basis of my ability to "nail" it -- quite recently