Persistent Systems Limited interview experience Real time questions & tips from candidates to crack your interview
SDE - 1
Persistent Systems Limited
3 rounds | 8 Coding
problems
Rejected
Interview preparation journey
Journey
I have started learning CP from You tube videos and then practising it through Hackerrank first, after felt enough confidence, I have started codeforces with the basic c++ knowledge, After that I have done 2 projects , and then started learning DSA topics and practising it from interview bit and leetcode. Have learned Computer fundamentals topics also.
Application story
I first applied through my campus placements, then through their career portal. After that, there was an online assessment. Candidates who were selected received a call for the interview round.
Why selected/rejected for the role?
I also don't know. My feedback from the second round of interviews was positive, yet two of us were rejected while two others received offers.
Preparation
Duration: 12 months
Topics: Data Structures, Competitive Programming (CP), Object-Oriented Programming (OOPS), Operating Systems (OS), Algorithms, Database Management Systems (DBMS), SQL, Computer Networks (CN)
Tip 1: Try to solve as many hard questions on online coding platforms as possible.
Tip 2: Complete at least two projects: one full-stack and the other either on the frontend or backend.
Application process
Where: Campus
Eligibility: No criteria (Salary: 12 LPA)
Tip 1: You must know everything about what you mention in your resume.
Tip 2: Every point in the resume must be precise and written in bullet points.
Interview rounds
01
Round
Medium
Online Coding Test
Duration60 minutes
Interview date5 Nov 2023
Coding problem2
1. Check If Linked List Is Palindrome
Easy
15m average time
85% success
0/40
Asked in companies
You are given a Singly Linked List of integers. You have to return true if the linked list is palindrome, else return false.
A Linked List is a palindrome if it reads the same from left to right and from right to left.
Example:
The lists (1 -> 2 -> 1), (3 -> 4 -> 4-> 3), and (1) are palindromes, while the lists (1 -> 2 -> 3) and (3 -> 4) are not.
Problem approach
1. First, we need to reverse the second half of the linked list.
2. Then, we take two pointers: one pointer points to the first node, and the other points to the head of the second half of the linked list.
3. Next, we move each pointer one step at a time and check whether the values at both pointers are the same or not.
2. First Repeated Character
Moderate
30m average time
70% success
0/80
Asked in companies
You are given a string 'STR' of lowercase English alphabets. You need to find the repeated character present first in the string.
Example:
If the string is: “abccba”, then the first repeated character is ‘c’, but the repeated character that is present first in the string is ‘a’. You need to print ‘a’.
Note:
Keep in mind that you need to print the repeated character that is present first in the string and not the first repeating character.
Problem approach
It's an easy problem. By using a map, we can solve this problem easily.
02
Round
Easy
Video Call
Duration60 minutes
Interview date4 Dec 2023
Coding problem3
1. DBMS
What are the advantages of a NoSQL database?
2. DBMS
SQL query to list all students and their scholarship amounts, if they have received any. If a student has not received a scholarship, display NULL for the scholarship details.
3. Reverse Words In A String
Easy
10m average time
90% success
0/40
Asked in companies
You are given a string 'str' of length 'N'.
Your task is to reverse the original string word by word.
There can be multiple spaces between two words and there can be leading or trailing spaces but in the output reversed string you need to put a single space between two words, and your reversed string should not contain leading or trailing spaces.
Example :
If the given input string is "Welcome to Coding Ninjas", then you should return "Ninjas Coding to Welcome" as the reversed string has only a single space between two words and there is no leading or trailing space.
Problem approach
Using a Stack: Push all words separated by a dot into the stack. Set the string to empty. Pop all words one by one from the stack and append them back into the string.
03
Round
Medium
Video Call
Duration60 minutes
Interview date4 Dec 2023
Coding problem3
1. Binary Tree Zigzag Traversal
Easy
15m average time
85% success
0/40
Asked in companies
You have been given a Binary Tree of 'N' nodes, where the nodes have integer values. Your task is to print the zigzag traversal of the given tree.
Note:
In zigzag order, level 1 is printed from left to right fashion, level 2 is printed from right to left. and level 3 is printed from left to right again, and so on…..
For example:
For the given binary tree
The zigzag traversal is [1, 4, 3, 5, 2, 7, 6]
Problem approach
Initialize two stacks, say currentLevel and nextLevel. Push the root node into the currentLevel. Initialize a boolean variable leftToRight, which will indicate the direction of traversal (initially set to true).
Repeat until the currentLevel stack is empty:
- Initialize a variable size to represent the size of the current level.
- Start traversing until size is not equal to 0.
- Pop from the currentLevel stack and push the node's value into the ans vector.
- If the current level order is from left to right, push the left child node into the nextLevel stack, then push the right child node. (Since the stack follows the last-in, first-out structure, in the next level traversal, the right child node will be popped first.)
- If the current level is from right to left, push the right child first, then push the left child.
- Swap the currentLevel and nextLevel stacks, and flip the value of leftToRight.
Finally, return the ans vector, whose elements follow the ZigZag Tree Traversal.
2. Operating System
What is virtual memory, semaphores, and some basic questions?
3. DBMS
SQL query to fetch the last five records from a table.
Here's your problem of the day 
Solving this problem will increase your chance to get selected in this company
Skill covered: Programming
What is recursion?
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