Amazon Interview Experience for SDE (Dublin) Feb 2022

Pattern: Given in September 2021(don’t lose hope. I got to interview 5 months after OA). 2 LC medium, behavioral questions, SDE simulation. 3 1-hour interviews(on the same day. 2 interviews without break and 30 mins break before the 3rd interview)
Each interview followed the same pattern:

• 30 mins – behavioral/LP questions
• 30 mins – code

Interview 1: 30 mins,  behavioral/LP questions(about teamwork, how you helped a friend). Followed by the following question:

• given: int[] timestamps and double[] values. For each timestamp, we have values given and we want to aggregate(sum) those values to a resolution of 1 minute. Timestamps are given at a resolution of a second. (hashmap). In the above question, he wanted to give the resolution as a parameter and not hardcode it to 1 minute, and also instead of just aggregating he wanted me to calculate its average. (hashmap<Integer, double[]> where double[] holds sum on 1st index and freq on 2nd and at the end, we would do double[0]/double[1] to get avg.)
• can’t remember but was an easy level only

Interview 2: Behavioral/LP questions(about customer satisfaction, tell me a time when you went out of your way to…, a time when you did something without asking your manager).

• system design. The question was we would be given some conditions and based on those conditions we had to filter out the files on a file system. (me being the stupid me and with no knowledge of system design I told them that you can have statements in a particular format and we can take arg as String[] instructions and then filter files but he said that was the unexpected solution(by that he meant unexpectedly stupid). In the end, he told me to make an interface for each filter we wanted to apply).

Interview 3: Behavioral/LP questions(about diving deep). Then he asked following questions: 

• isSameTree(Node a, Node b) -> self explanatory I guess
• find the missing number. (arr from 1…N)
• find a complete 3-node binary tree inside a larger tree

Discussed space and time complexity for all.