Deloitte Software Developer Interview Questions, Process, and Tips

Round duration - 135 minutes
Round difficulty - Easy

Coding questions was easy if you know the basic of coding in any language. I submitted optimized solution for every questions that's why i got selected in this round.

Q1. Find K’th Character of Decrypted String
You have been given an Encrypted String where repetitions of substrings are represented as substring followed by the count of substrings.
Example: String "aabb...read more
Ans. Decryption
We will just iterate through Encrypted String ‘S’ and will create a Decrypted String. Then we can print the K’th character of Decrypted String.
• We will find the substring by traversing the string until no digit is found.
• Then find the frequency of the preceding substring by traversing the string until no lowercase alphabet is found. We can use this relation to create the Integer frequency from the string:
  • freqOf...read more
Answered by CodingNinjas
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Q2. Cycle Detection In Undirected Graph
You have been given an undirected graph with 'N' vertices and 'M' edges. The vertices are labelled from 1 to 'N'.
Your task is to find if the g...read more
Ans. DFS Approach (Slow)
There is a cycle in the graph only if there is a back edge (back edge is an edge that connects a vertex to another vertex that is discovered before it's parent) present in the graph. To detect a back edge, we will keep track of vertices that have been already visited. If we reach a vertex that is already visited and is not the parent vertex of the current vertex, then there is a cycle in the graph.&n...read more
Answered by CodingNinjas
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Round duration - 150 minutes
Round difficulty - Medium

Q1. Pair Sum
You are given an array/list ‘ARR’ consisting of ‘N’ distinct integers arranged in ascending order. You are also given an integer ‘TARGET’. Your task is to count all the distinct pairs in ‘ARR’ suc...read more
Ans. Brute Force
First, we declare a variable 'COUNTPAIR’ in which we store all pairs whose sum is equal to 'TARGET’. Then, we traverse the array ‘ARR’ and assume every element as the first element of the pair. Then we again traverse the remaining array and consider every element as a second element of the pair, and check whether the sum of the two elements is equal to 'TARGET' or not. If it is equal to 'TARGET',’ then we in...read more
Answered by CodingNinjas
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Q2. Next smaller Palindrome
You are given a number 'N' in the form of a string 'S', which is a palindrome. You need to find the greatest number strictly less than 'N' which is also a pa...read more
Ans. Brute Force
• Given the fact that the input number is a palindrome itself makes this problem very trivial.
• Let us assume that the given string str is a palindrome, so we know that ‘S’ comprises of two halves  ‘S₁’ and ‘S₂’ i.e ‘S’ = ‘S₁' + ‘S₂', where ‘S₁' and ‘S₂’ are two strings, and ‘S₂’ is the reverse of ‘S₁’(in case of odd length palindromes ‘S₂’ won’t have the last character of ‘S₁’). So a change in any of the h...read more
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Q3. Longest Common Subsequence
You have been given two Strings “STR1” and “STR2” of characters. Your task is to find the length of the longest common subsequence.
A String ‘a’ is a subsequence of a String ‘b...read more
Ans. Recursive Brute Force
The basic idea of this approach is to break the original problem into sub-problems. Let us assume we want to find the length of the longest common subsequence of “STR1” and “STR2” whose length is ‘N’ and ‘M’ respectively. 
 
Now, let us define a recursive function 
 
LCS(Int I, int J, string STR1, string STR2)
Which returns the length of the longest common subsequence of string STR1...read more
Answered by CodingNinjas
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Round duration - 30 minutes
Round difficulty - Easy

Interview went well.The interviewer asked me how the previous interviews were.

Q1. Boundary Traversal
You have been given a binary tree of integers. Your task is to print the boundary nodes of this binary tree in an Anti-Clockwise direction starting from the root node.
NOTE: The bounda...read more
Ans. Recursion based Approach
The boundary traversal of a binary tree can be broken down into 4 parts. These parts are given in the same order as they are present in the traversal-
1. The root node - The root node will always be our first node in the whole boundary traversal.
2. The left boundary - The left most nodes of the left subtree are also included in the boundary traversal, so we will process them next except for the leaf no...read more
Answered by CodingNinjas
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Q2. Sort 0 1 2
You have been given an integer array/list(ARR) of size 'N'. It only contains 0s, 1s and 2s. Write a solution to sort this array/list.
Note :
Try to solve the problem in 'Single Sca...read more
Ans. Sorting
Use any good sorting algorithm like Merge Sort, Quick Sort or inbuilt sorting function of different languages.
• Sort the Array and just return.
Space Complexity: O(1)Explanation:
O(1), As we are using constant space.
Time Complexity: O(nlogn)Explanation:
O(N*log(N)), where ‘N’ is the size of the array.
We are using inbuilt sort algorithm which has Overall Time Complexity O(N*log(N))
Answered by CodingNinjas
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Round duration - 20 minutes
Round difficulty - Easy

This round is very easy, In this round they basically need confidence and truthful person.

Q1. Basic HR Questions
Where do you see yourself in 5 years?
What are your weaknesses?
Ans. 
Tip 1 : Just be confident
Answered by CodingNinjas
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It was moderate one

Hard one

Round duration - 90 Minutes
Round difficulty - Medium

This round happened on the same day as JAM in the afternoon time. A slot of 20 minutes with respective timing was already sent to the selected students. Interview can’t be generalize as anything can happen over there and hence this was exclusively my experience. 
To have a quick judgement about the person, I believe nothing is better than throwing before him/her some puzzles (mathematical/ analytical/ programming problems) and see the approach. I received back-to-back 4 problems after a quick and brief introduction. The coding problems I got were way too easy (just basics: searching & mathematical). The harder part of this round was the puzzles (tricky, mathematical, related to probability). At last, I was asked a question on DBMS and the interviewer asked if I know JAVA.

Q1. Search an Element in an Array
You have given a sorted array 'A' of 'N' integers.
Now, you are given 'Q' queries, and each query consists of a single integer 'X'. Your tas...read more
Ans. Brute Force
The idea here is to do a linear search which apparently is a brute force way, so for each query:
1. Visit every element one by one.
2. Check if the current element is equal to X or not. If yes, then we will add 1 to the answer.
3. Once all the elements are visited, and we don't find the X value, then add 0 to the answer.
Space Complexity: O(1)Explanation:
O(1).
 
In the worst case, a constant space is required.
Time Co...read more
Answered by CodingNinjas
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