Flipkart Interview Experience | SDE-1 (Experienced)

Round 1: Machine Coding Round (1.5 hrs)

I was  given  the following problem statement and asked to  implement it with any choice of programming language.  They expected the code to be production-level, modular and bug free. After this, there was an evaluation round for the code. They tested the code with all corner cases and asked me to modify the code for new requirements which I was able to do easily.

JobScheduler

A job scheduler to schedule M jobs on N threads on a single machine. The input contains the following data:

1. Job Name
2. Duration: time taken for job completion
3. Priority: priority of the job. P0>P1>P2
4. Deadline: Expiry time after which job should not be run (The clock starts from 0 and deadline is the actual clock time)
5. UserType: Type of user who has initiated the job, Precedence of users Root>Admin>User

There are various scheduling algorithms-

Shortest Job First – SJF

Shortes job first (SJF), is a scheduling policy that selects the waiting process with the smallest execution time to execute next. In case of tie choose the job according to the following order-

1. Priority(higher priority job gets scheduled first)

First Come First Serve -FCFS

Jobs are executed on first come, first serve basis. Take the input as the order of jobs need to be scheduled.

Fixed Priority Scheduling -FPS

Each process is assigned a priority. Process with highest priority is to be executed first and so on. In case of tie choose the job according to the following order-

1. User Type
2. Longest Job First

Earliest Deadline First – EDF

Next job will be searched on the basis of job which is closest to its deadline. In case of tie, choose the job according to the following order-

1. Priority(higher priority job gets scheduled first)
2. Duration(lesser duration job gets scheduled first) In case we cannot schedule a job such that it completes before its deadline then it should be ignored.

You would be given a list of jobs (refer example below for format) and number of threads as input. You are expected to print the order of jobs scheduled for each algorithm on each thread as output.

Example

Input

Threads= 2

Job Name	Duration	Priority	Deadline	User Type
J1	10	P0	10	Root
J2	20	P0	40	Admin
J3	15	P2	40	Root
J4	30	P1	40	User
J5	10	P2	30	User

Output

SJF
Thread 1 - J1, J3, J4
Thread 2 - J5, J2

FCFS
Thread 1 - J1, J3, J5
Thread 2 - J2, J4

FPS
Thread 1 - J1, J4, J5
Thread 2 - J2, J3

EDF
Thread 1 - J1, J2
Thread 3 - J5, J4

Round 2: PS-DS Round (1 hr)

This was a problem solving and data structures related round.

Interviewer asked me following questions with working code.

1. At any point of time, find the average of max k numbers from an incoming stream of infinite numbers. I solved it using min-heap of k size and maintaining a sum variable to find the average. For every insertion to min-heap add the element to sum and for every deletion from min-heap, subtract the element from sum.  To get the average return sum/no. of elements.
2. Copy the contents of  a given stack to another stack in same order without using extra space.
3. Rain water trapping problem. https://www.geeksforgeeks.org/trapping-rain-water/

I solved all of the above problems and my interviewer was satisfied.

Round 3: Hiring Manager Round (1 hr)

The HM had  an in-depth discussion on my latest project and technologies that I had used in the project.He asked me a lot of behavioral questions as well.

After a few weeks I got the offer.