Amazon System Development Engineer L4 | Bangalore

Initially had OA with 2 medium level qn, i remember it was in hackerrank (Not so sure) dont remember the qns exaclty. All test cases passed followed by nearly 30-50 mcqs scenario based qns.

Interview Round1:

Introduce yourself
oops
whats abtsraction ? encapsulation?
medium level coding
Given array of customerIds sorted in ascending order visited to amazon store. Get the number of time customer visited based on the input customer id.
eg: [1,1,2,2,3,4,4,4,4,5,6,7,7,7,7,7,7,8,8]
input: 7
output: 6

Initially given a linear solution, asked to optimize.
Optimized it to logN by using binarySearch.
binary search 3 times , 1st time to find element . Next call to find the 1st occurence of the customer id and next call to get the last occurence of customer id, return last-first index as resut

Asked in previous org have you faced any issue where u had to analyze and find rca. Explained it.

Hr scheduled 2 interviews after the OA , done with one round.

Round2
This round focus was more on scripting and linux.

introduction
Most challenging task done in previous organisation
Asked whether you looked on something significant thats outside of your area of responsibility and asked to explain
Have you fced any risk or commitment deadline and how its handled

In a linux vm , we have list of log files, search for : Processed Record {name: anyname, type:shirt,....} . Find the no of occurence of above pattern in each file and print. Asked to tell the approach and later asked if i can give a soln using any linux commands /scripting
In a linux vm, there is a process that need to be run always. There was an issue that application was not running? How to debug?
List of ids present in a file. How do you identify distinct ids from the file?

I got rejected in the 2nd round.
If there is any other good approch for above feel free to add it in comment