Amazon Software Development Engineer (SDE) interview questions

In first round the interview asked me that you work in amazon and have to make module where you have to deal with large dataset of mobile phone . Then asked to write code for different queries like mobile phone having price above 15000. Then, if data is frequently being added how will you carry on, which dataset will you use.

Could you give an example of a situation where you had to dive deep into problem in order to find a solution? Why Amazon? Recursions, Backtracking prob