Junior Software Engineer EPAM Systems interview experience

Interview rounds

Round

Medium

Online Coding Interview

Duration60 Minutes

Interview date16 Dec 2021

Coding problem1

This round was completed on my anatomy platform and in this round 20-25 mcqs were asked which are based on java output and java theoritical mcqs.
One DSA coding question has came in this round which is of easy level question of array based and have to do that question in only java. This round is of 60 minutes and you have to complete both part on this duration

1. Squares of a Sorted Array

Easy

15m average time

85% success

0/40

Asked in companies

You are given an array/list ‘ARR’ of ‘N’ integers. You have to generate an array/list containing squares of each number in ‘ARR’, sorted in increasing order.

For example :

Input:
‘ARR’ = [-6,-3, 2, 1, 5] 

If we take a square of each element then the array/list will become [36, 9, 4, 1, 25].
Then the sorted array/list will be [1, 4, 9, 25, 36].

Output :
[1, 4, 9, 25, 36].

Problem approach

step 1 : use two pointer one at 0 index and 2nd at last index and traverse from last
step 2 : check if square of element at index of pointer1 is less than square of element at index of pointer2 then store square of element of index pointer2 at position of pointer2 and then decrease pointer2
step 3 : else store the element at pointer1, swap the element at pointer1 and pointer2 then store square of stored result and decrease pointer 2
step 4 : in this way we have received a sorted array of square

Try solving now

Round

Hard

Online Coding Test

Duration60 Minutes

Interview date20 Dec 2021

Coding problem3

In this round 3 DSA problem was asked. One was easy , 2nd was medium level and third was hard level. These problem are based on stack , linkedlist, string,array manipulation. and 3rd one was based on Dynamic Programming.

1. Largest rectangle in a histogram

Hard

25m average time

75% success

0/120

Asked in companies

You have been given an array/list 'HEIGHTS' of length ‘N. 'HEIGHTS' represents the histogram and each element of 'HEIGHTS' represents the height of the histogram bar. Consider that the width of each histogram is 1.

You are supposed to return the area of the largest rectangle possible in the given histogram.

For example :

In the below histogram where array/list elements are {2, 1, 5, 6, 2, 3}.

The area of largest rectangle possible in the given histogram is 10.

Problem approach

step 1 : create array and store NSE index to the right.
step 2 : create array and store NSE index to the left.
step 3 : Iterate through the given array.
width will be right index - left index + 1
height is array[index]
area is height*width,
And maximum of all the area resultant is our answer

Try solving now

2. Remove Duplicates From an Unsorted Linked List

Moderate

15m average time

85% success

0/80

Asked in companies

You are given a linked list of N nodes. Your task is to remove the duplicate nodes from the linked list such that every element in the linked list occurs only once i.e. in case an element occurs more than once, only keep its first occurrence in the list.

For example :

Assuming the linked list is 3 -> 2 -> 3 -> 4 -> 2 -> 3 -> NULL.

Number ‘2’ and ‘3’ occurs more than once. Hence we remove the duplicates and keep only their first occurrence. So, our list becomes : 3 -> 2 -> 4 -> NULL.

Problem approach

step 1 : Use two pointer, one ptr point to dummy node and second ptr point to head node
step 2 : check for ptr1 next is equal to ptr2 if true ,
then move ptr2 to its next position
else
we made connecttion between ptr 1 and ptr1 next and point ptr 1 to pt1.next and move ptr2 by one position
step 3 : so in this way we acheive our resultant LL
step 4 : so dummynode`s next node is our head node of resultant LL.

Try solving now

3. Minimum Swaps To Make Two Strings Equal

Hard

30m average time

85% success

0/120

Asked in companies

You are given two strings, ‘s1’ and ‘s2’, each of length ‘N’. The strings ‘s1’ and ‘s2’ are anagrams (i.e., they contain the same characters). You can swap the position of any two characters in ‘s1’ any number of times. The task is to find the minimum number of swaps we need to perform to make ‘s1’ equal to ‘s2’.

Example :

s1 = “bac”, s2 = “acb”, n = 3

We need to perform at least two swaps to make ‘s1 = s2’:
1. Swap ‘b’ and ‘a’, so:
    s1 = “abc”
2. Swap ‘b’ and ‘c’, so:
    s1 = “acb”
So, the answer is ‘2’.

Problem approach

step 1 : First I applied LCS (Longest Common Subsequence) technique and find the length of LCS
step 2 : Now subtracting length of LCS with lengths of individual strings gives us number of characters to be removed to make them identical.
step 3 : Now mutiply cost string X with the result obtained above + same with string y

Try solving now

Round

Medium

Group Discussion

Duration30 minutes

Interview date23 Dec 2021

Coding problem0

they have given a random topic and we have to express our views on them. one interviewer is there and 8 students and we have to talk to about that topic. One topic is given to all and then interviewer given 2 minutes to think about it then started the conversation and we have brief about it then how safe and how it is bad and so on. At last it concludes all the pts have been putted by students. this round go till 30 minutes

Round

Hard

Video Call

Duration60 Minutes

Interview date27 Dec 2021

Coding problem1

This round was technical round and this round wents for 60 minutes and in this round and interviewer has came and he has asked about the basic concept of oops , java based output question, talked about my projects which i mentioned on my resume and majorly this round focus on java oops questions.

1. Technical Questions

use of static keyword, Abstract class vs interface, Oops concept., Collection class
Execption handling, Explain different Data Strcutures,
Access modifiers,
difference between singly linked list and circular linked list,
stack implementation

Round

Medium

HR Round

Duration30 Minutes

Interview date30 Dec 2021

Coding problem1

This round was HR round and it wents for 30 minutes. In this interviewer asks about various question about my resume.
Tell me about your projects, whether it was a team project or individual.
leadership skills you have
My hobbies
family background
college projects