Delhivery Interview Experience for Backend Developer On Campus(Nov 2018)
Online Test:This round was conducted online on hackerearth for 2.30 hours.It had 2 sections
Section 1: It consisted of 49 MCQ questions related to data science, data structures, Sql, computer networks, operating systems.
The MCQ’s were of different marks.Some of the questions had negative marking while some didn’t.
Section 2: It was coding section consisted of 3 questions.
- There are t test cases.For each test case, given two numbers m, n, k and a prime number p.
First you have to count number of times p occurs in the prime factorization
of all numbers in the range of [m, n] then return k*count.[20 marks]
Constraints: t<10^5, m, n<10^9, p<10^6, k<10^6.
Test Case: m=6, n=8, k=5, p=2
ans : 20
6=2*3, 7=7, 8=2*2*2
therefore count of 2 is 4
- Given a directed Graph find a node in the graph such that if we start a dfs
from that node we can reach maximum number of nodes.[20 marks]
- Given a string consisting of * and # and two variables r1, r2.Starting from the first index of the string you have to find minimum number of steps required to reach the last index without landing on a * character index.You can move from every * marked index i to (i+1) and (i+2) in one step.Also you can move to (i+A) if (A/i)>=(r1/r2), where A is the number of prime numbers from 1 to i.Print “No Way” if it is impossible to reach the nth index.[50 marks] Test case: string = #*###### r1=1 r2=2ans : 3(1->3->5->8).
This round was of 262 marks.
I was able to do 19 MCQ’s and 2 coding questions.
Around 250 appeared in the Round1 and 34 were selected.
Round 1: The interviewer asked me to introduce myself and then he started discussing my projects in depth.
After that he started putting up questions related to OOP.
Four pillars of oops?
Difference between method overloading and overriding with example.
What is diamond problem in oops?
Will there be the error in code if during function overloading if we change the return type of function?Justify your answer.
What is abstract class?
and then he asked questions related to DBMS:
1.What is normalization and explain 1NF and 2NF with examples.
2.What is indexing?
3.Explain the ACID properties?
Then started asking questions related to sorting like selection sort, heap sort and quick sort
On which algorithm paradigm quick sort works.
Then he gave me coding question.
Given a string of parentheses you have to tell whether the string is balanced or not.
He told me to write the code.
This round went for almost 1 hour.
Round 2:After waiting for 2 hrs I was called for this round.
Again, the interviewer asked me explain my recent project. why i used MongoDB in my project.
Why I used mongodb instead of mysql.
Which function is used in MongoDB to search for a result.
Difference between schema and non-schema database.
Then he, asked what is indexing in database.
As i have mentioned that i used API in one of my projects so he told me to explain API?
Then he asked questions related to Operating systems.
1.Difference between process and thread.
2. Difference between multi-threading and multiprogramming
This round went for around 40 minutes.
HR Round:In this round I was told that I have been selected.
I was given option to choose between Gurgaon and Hyderabad.