Tip 1 : Have problem solving mindset, not only learning solution of standard question
Tip 2 : Have little knowledge of how to design the system(low level)
Tip 1 : Have projects
Tip 2 : Have coding profile links
Problem was easy, the main thing was to write it without bug and in the first go also.
I specify my approach of backtracking and and explain while drawing also. Then code.
You are to design the smart lift system for the building. Design only for the lift.
How you make the classes, how you handle the concurrent input, how you will store the input and all.
And the input can be taken from 2 side, one is from inside lift and other is from outside (2 buttons, upward and downward.)
Tip 1 : Don't just go and try to solve the question. Ask question and specify what needs to be build.
Tip 2 : Must have clear concept of OOPs and have practise how to solve these type of question.