# Delhivery Interview Experience for Backend

• Difficulty Level : Easy
• Last Updated : 12 Sep, 2018

Round 1(Online):
49 MCQ questions related to Data Science and Programming
Coding Question:
Question 1:
Given a Directed Graph at most 1 edge coming out of it. Find the node if started traversing from that node covers the maximum node. (20 marks.)
(Hint- DFS from every node output which will cover maximum nodes.)
(Try brute force).
Question 2:
There a t-test cases. For each test case, given two numbers m, n, and a prime number p. You have to count a number of times p occurs in the prime factorization of all numbers in the range of being, n] (20 marks).
Constraints: t<10^5, m, n<10^9, p<10^6 Test case: m=6 n=8 p=2 Ans : 4(6=2*3, 7=7, 8=2*2*2 therefore count of 2 is 4) Question 3: Given a string consisting of * and # and two variables r1, r2. Starting from the first index of the string you have to find a 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=2
and : 3(1->3->5->8).

Round 2(F2F):
So In this interview like other interviews I was expecting tell me about yourself but no he started like the thing you are most proud of in your CV.

Coding question –

you are given
name value
A 1
A 3
B 1
B 6
B 7
B 1
B 6
C 87
C 1
C 6
N 7
U 45
Print:
A 1
A 3
B 1
B 6
C 87
C 6
N 7
U 45

Basically first and last of every occurrence and there is only one then print only first occurrence.
It is an easy question. I wrote the bug-free code so he was impressed.

Question 2)(Nightmare for me)
Given: 5+3*2-1+8*7
generate all possible combinations
like one possibility would be (8)*(2-1)+(56)
=8*1+56=8+56=64
or
I tried very hard but couldn’t solve it. He made me solve it for 30 minutes and tell him the approach but I was unable to do it.
I was very scared after that one as this was a bad sign.

Question 3)  Tell me different about types of Inheritance

Question 4) Tell me different about types of Polymorphism.

Question 5) You are given some interfaces and a class implements them all, find the number of interfaces implemented
PS:- If you understand this one explain me as well

Question 6) Difference between windows and Linux

After asking these questions he asked me do you have any questions for me so I asked him what kind of language do you use in the company and the projects
for 15 minutes he explained to me different micro-services used in Delhivery and how they interact with each other and what will happen if one fails.
After This discussion, I was really interested in the projects of Delhivery.
After this round, I was convinced I will not make it through it but I don’t know how my second round happened

Round 3(F2F):
Then comes this guy he asked me to rate my Computer Science Subjects how much I know about them. I rated Data Structures and Algorithms at the top and Computer Networks and OOP, last and Second last.
Obviously, he started with Computer Networks
Explain what happens when you hit google.com.
Explain Domain Name System
Then I told him I am not comfortable with CN course.
SO then he moved to OOP
Asked me about Diamond Inheritance Problem. (I Didn’t Knew )
and solve it.

Then every OOP concept you think of(Learn OOP please if you want to join Delhivery)

Then he moves to DBMS
Different types of Joins in DBMS
Asked me to write code for joins in MYSQL. (He helped me through it Kinda cool guy though).

Then At last DS and Algo(Not very hard I would say it was more of a discussion than an interview)

Explain Tail recursion.
What is DP? Why do we memoize?
Binary Search question and implementation
Print matrix in spiral Order and code.

After this what are your expectations from Delhivery
I told him what I understood in first round different microservices.
I said I want to understand how they work.

Round 4 (Face to face)
This was an HR round
Asked me about my Strength and weakness answer very carefully they will seriously make you sweat if you think you cannot defend what you say.