Reliance Retail Java Developer Interview Questions and Answers

Coding questions on String and HashMap

2 coding questions and a few MCQs

Q1. Asked to explain and optimise my solution from coding test
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Q1. Behavioral round. Asked about resume.
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Q1. General HR round and trying to find if you're a right fit for the company
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2 coding questions from dsa. one quest was from trees ds

Q1. Why did you choose target
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Q2. Minus points in you that you can share with us
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Q1. Kafka , heap stack
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Q2. Mvc endpoint creation
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Q1. Dsa on string please
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Q2. Heap
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The test was quite simple but the interviewer was not ready to accept the solution. Even with complete dry run and working output he denied the solution giving a very vague reason.

Q1. In this design round , they asked me to demonstrate how to build cowin app. Gave a complete overview including HLD and LLD for each showcased feature still got negative response.
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2 DSA questions and some MCQ on Java and Spring

Q1. Longest palindromic substring
Ans. 
A palindromic substring is a string that reads the same forwards and backwards.
• Use dynamic programming to find the longest palindromic substring.

• Start by considering each character as the center of a potential palindrome.

• Expand outwards from each center to check for palindromes of odd and even lengths.
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Q2. Remove duplicates in place from a 1D array
Ans. 
Remove duplicates from a 1D array of strings in place
• Iterate through the array and use a HashSet to keep track of unique elements

• Replace duplicates with null or an empty string to remove them in place
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Q1. Project discussion
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Q2. Search min element in a rotated sorted array with duplicate elements
Ans. 
Search for the minimum element in a rotated sorted array with duplicate elements.
• Use binary search to find the minimum element in the rotated sorted array.

• Handle the case where duplicate elements are present by adjusting the search conditions.

• Consider cases where the array is not rotated or contains only one element.
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Q3. Ways of declaring singleton class
Ans. 
A singleton class is a class that can only have one instance created throughout the application.
• Declare a private static instance variable of the class

• Create a private constructor to prevent external instantiation

• Provide a public static method to access the instance
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Q1. Project discussion
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Q2. Behavioural questions
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Round duration - 90 minutes
Round difficulty - Medium

This was a proctured online coding round where we had 2 questions to solve under 90 minutes . The questions were a bit lengthy but the implementation part was quite easy .

Q1. Encode the Message
You have been given a text message. You have to return the Run-length Encoding of the given message.
Run-length encoding is a fast and simple method of encoding strings. The basic idea...read more
Ans. 
Steps:
1) Sort all the words in descending order of their lengths.
2) Initialise res with first word in the vector + "#"
3) Now we just need to find, if other words in the vector + # are substring of res or not. if not, append that word to res.
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Q2. Make all elements of the array distinct.
You have been given an array/list ‘ARR’ of integers consisting of ‘N’ integers. In one operation you can increase an element by 1. Your task is to return the minimu...read more
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Steps:
1) The idea is to sort the input , then we move forward from the beginning of the array till the end.
2) As soon as we found a condition that the current element is less than or equal to the previous elements then we need to update the current array element by adding 1 to its prev element .
3) At the same time we need to keep track of result by result += A[i-1]- A[i]+1;
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Round duration - 50 Minutes
Round difficulty - Easy

This Round was DS/Algo + Core round and it started with formal introduction, followed by 3 problems. We first dicussed the
approach the time complexity and proper code covering all cases for the 2 coding problems . The last question was related to OS and was a bit theoretical .

Q1. Distinct Characters
Given a string “STR”, you need to return all the possible non-empty subsequences with distinct characters. You can return the strings in any order.
Note:
If the same string can be gen...read more
Ans. 
Instead of counting all unique characters and struggling with all possible substrings,
we can count for every char in S, how many ways to be found as a unique char.
We count and sum, and it will be out answer.

Let, index[26][2] record last two occurrence index for every upper characters.
1) Initialise all values in index to -1.
2) Loop on string S, for every character c, update its last two occurrence index to index[c].
3) C...read more
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Q2. NINJA’S PARENTHESES
One day Ninja goes to play some intellectual games. There was a game where Ninja is given a string of balanced parentheses 'STR' and he has to calculate the score of that using ...read more
Ans. 
Approach 1 : 

Every position in the string has a depth - some number of matching parentheses surrounding it. For example, the dot in (()(.())) has depth 2, because of these parentheses: (__(.__))

1) Our goal is to maintain the score at the current depth we are on. 
2) When we see an opening bracket, we increase our depth, and our score at the new depth is 0. 
3) When we see a closing bracket, we add twice th...read more
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Q3. OS Question
Explain demand paging
Ans. 
Demand paging is a method that loads pages into memory on demand. This method is mostly used in virtual memory. In this, a page is only brought into memory when a location on that particular page is referenced during execution. The following steps are generally followed:

1) Attempt to access the page.
2) If the page is valid (in memory) then continue processing instructions as normal.
3) If a page is invalid then a page-f...read more
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Round duration - 40 Minutes
Round difficulty - Medium

I was given 2 preety good questions of DSA in this round . One was related to Binary Trees and the other was a good DP problem in which I struggled a bit but with some hints I was able to solve this problem too . The last question was related to OOPS and was preety easy .

Q1. Create a binary tree from postorder and preorder traversal
You are given the ‘POSTORDER’ and ‘PREORDER’ traversals of a binary tree. The binary tree consists of ‘N’ nodes where each node represents a disti...read more
Ans. 
We will preorder to generate TreeNodes, push them to the stack and perform postorder to pop them out.

1) Iterate on pre array and construct node one by one.
2) Stack saves the current path of the tree.
3) node = new TreeNode(pre[i]), if not left child, add node to the left. otherwise add it to the right.
4) If we meet a same value in the pre and post, it means we have completed the construction for current subtree. We pop
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Q2. Minimum Cost To Buy Oranges
You are given a bag of size 'W' kg and provided with the costs of packets with different weights of oranges as a list/array with the name 'cost'. Every i-th posi...read more
Ans. 
This problem was actually a variation Unbounded Kanpsack Problem . I first gave the interviewer a naive recursive
approach and then later optimised it using memoisation .

Naive Recursive Approach :

1) Create a recursive function ( int minCost(cost, idx , w) ) which returns the optimal answer for an array which starts
with index idx and for a given weight w.

2) Now for every index idx , if cost[idx]!=-1 then I have three opt...read more
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Q3. OOPS Question
Static and Dynamic Polymorphism
Ans. 
Static polymorphism (static binding) is a kind of polymorphism that occurs at compile time. An example of compile-time polymorphism is method overloading.

Runtime polymorphism or dynamic polymorphism (dynamic binding) is a type of polymorphism which is resolved during runtime. An example of runtime polymorphism is method overriding.
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Round duration - 30 Minutes
Round difficulty - Easy

This is a cultural fitment testing round .HR was very frank and asked standard questions. Then we discussed about my role.

Q1. Basic HR Question
Why should we hire you ?
Ans. 
Tip 1 : The cross questioning can go intense some time, think before you speak.
Tip 2 : Be open minded and answer whatever you are thinking, in these rounds I feel it is important to have opinion.
Tip 3 : Context of questions can be switched, pay attention to the details. It is okay to ask questions in these round,
like what are the projects currently the company is investing, which team you are mentoring. How all is the ...read more
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Q2. Basic HR Question
Do you know anything about the company ?
Ans. 
General Tip : Before an interview for any company , have a breif insight about the company , what it does , when was
it founded and so on . All these info can be easily acquired from the Company Website itself .
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