The hiring process is fine, though my interviews were all scheduled for weekends. They typically have five rounds of interviews.

There is a preliminary round. If you pass that, there are three more rounds of technical interviews. After that, you might have one more round where you'll be interviewed by someone high up (in my case, it was a director).

Assume a text console where somebody is typing input. Whenever the person hits Enter, we should display the string that they have entered.

The string can be very, very long, and the program that takes the input and displays it should be as fast as possible. Write such a C program.

I was asked a variant of the Single Source Shortest Path Problem on a general tree.