Josh Technology Group Interview Questions, Process, and Tips

Excel only nothing else so don't worry about this

Q1. Only excel needed nothing more
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Q1. Only excel needed nothing more
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Q1. General discussion nothing more
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1 hour duration with basic level aptitude

1 hour 30 minutes, basic to medium level dsa

Round duration - 150 Minutes
Round difficulty - Medium

3 coding question + 50 dsa

Q1. 
Majority Element Problem Statement
Given an array/list 'ARR' consisting of 'N' integers, your task is to find the majority element in the array. If there is no majority element present, return -1.
Exampl...read more
Ans. 
Find the majority element in an array, return -1 if no majority element exists.
• Iterate through the array and keep track of the count of each element using a hashmap.

• Check if any element's count is greater than floor(N/2) to determine the majority element.

• Return the majority element or -1 if no majority element exists.
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Q2. 
Height of a Binary Tree
You are provided with an arbitrary binary tree consisting of 'N' nodes where each node is associated with a certain value. The task is to determine the height of the tree.
Explana...read more
Ans. 
Calculate the height of a binary tree given its level order traversal.
• Traverse the binary tree level by level and keep track of the height as you go down the tree.

• Use a queue data structure to perform level order traversal efficiently.

• The height of a binary tree is the maximum number of edges from the root to any leaf node.

• Handle NULL nodes represented by -1 in the input.

• Return the height of the binary tree as a single
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Q3. 
Number of Islands Problem Statement
You are provided with a 2-dimensional matrix having N rows and M columns, containing only 1s (land) and 0s (water). Your goal is to determine the number of islands in t...read more
Ans. 
Count the number of islands in a 2D matrix of 1s and 0s.
• Use Depth First Search (DFS) or Breadth First Search (BFS) to traverse the matrix and count the number of connected components.

• Maintain a visited array to keep track of visited cells to avoid counting the same island multiple times.

• Iterate through each cell in the matrix and if it is a land (1) and not visited, perform DFS/BFS to explore the connected land cells.

• I...read more
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Round duration - 60 Minutes
Round difficulty - Hard

2 coding questions

Q1. 
Maximum Length Pair Chain Problem Statement
You are given 'N' pairs of integers where the first number is always smaller than the second number, i.e., in pair (a, b) -> a < b always. A pair chain is...read more
Ans. 
Find the length of the longest pair chain that can be formed using the given pairs.
• Sort the pairs based on the second element in ascending order.

• Iterate through the sorted pairs and keep track of the maximum chain length.

• Update the chain length if the current pair can be added to the chain.

• Return the maximum chain length at the end.
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Q2. 
Maximize Stock Trading Profit
You are given an array prices, representing stock prices over N consecutive days. Your goal is to compute the maximum profit achievable by performing multiple transactions (i...read more
Ans. 
Find maximum profit by buying and selling stocks multiple times.
• Iterate through the array and find all increasing sequences of stock prices.

• Calculate profit by buying at the start and selling at the end of each increasing sequence.

• Sum up all profits to get the maximum profit achievable.
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Round duration - 45 minutes
Round difficulty - Medium

Data structures,java script,web dev related questions,dbms questions

Q1. Can you describe how to design a web crawler?
Ans. 
Designing a web crawler involves defining the scope, selecting a crawling strategy, implementing the crawler, handling data storage, and ensuring politeness.
• Define the scope of the web crawler by determining the websites to crawl and the depth of the crawl.

• Select a crawling strategy such as breadth-first or depth-first search based on the requirements.

• Implement the web crawler using a programming language like Python o...read more
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Round duration - 60 minutes
Round difficulty - Medium

Students who qualified in first round gets link for this round, this round had 4 questions in total, out of which 1 was output based and 3 was DSA based.

Q1. 
Validate Binary Tree Nodes Problem
You are provided with 'N' binary tree nodes labeled from 0 to N-1, where node i has two potential children, recorded in the LEFT_CHILD[i] and RIGHT_CHILD[i] arrays. Dete...read more
Ans. 
The task is to determine if the given binary tree nodes form exactly one valid binary tree.
• Check if there is only one root node (a node with no parent)

• Check if each node has at most one parent

• Check if there are no cycles in the tree

• Check if all nodes are connected and form a single tree
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Round duration - 75 minutes
Round difficulty - Medium

This round was of 70-75 minutes and had 3 coding questions of easy to medium level. There was some restrictions like we cannot use built-in functions in both second and third subjective round.

Q1. 
Balanced Binary Trees Problem Statement
You are provided with an integer 'H'. Your task is to determine and print the maximum number of balanced binary trees possible with height 'H'.
A balanced binary t...read more
Ans. 
The maximum number of balanced binary trees possible with a given height is to be counted and printed.
• A balanced binary tree is one in which the difference between the left and right subtree heights is less than or equal to 1.

• The number of balanced binary trees can be calculated using dynamic programming.

• The number of balanced binary trees with height 'H' can be obtained by summing the product of the number of balanced...read more
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Round duration - 60 minutes
Round difficulty - Medium

This was face to face interview round of 60 minutes. It was mostly based on DSA, some questions was also asked related to my projects and DBMS. Interviewer was kind and good.

Q1. 
Wave Array Sorting Problem
Your goal is to sort a given unsorted array ARR such that it forms a wave array.
Explanation:
After sorting, the array should satisfy the wave pattern conditions:
• ARR[0] &...read more
Ans. 
The task is to sort an array in a wave form, where each element is greater than or equal to its adjacent elements.
• Iterate through the array and swap adjacent elements if they do not follow the wave pattern

• Start from the second element and compare it with the previous element, swap if necessary

• Continue this process until the end of the array

• Repeat the process for the remaining elements

• Return the sorted wave array
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Q2. 
Maximum Sum BST Problem Statement
You are presented with a Binary Tree 'root', which may not necessarily be a Binary Search Tree (BST). Your objective is to identify the maximum sum of node values in any ...read more
Ans. 
The task is to find the maximum sum of node values of any subtree that is a Binary Search Tree(BST).
• Traverse the binary tree in a bottom-up manner

• For each node, check if it forms a BST and calculate the sum of its subtree

• Keep track of the maximum sum encountered so far

• Return the maximum sum
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Round duration - 135 minutes
Round difficulty - Hard

This was the final technical round, it was around 2.5 hours long and based on mostly DSA and little bit Projects, DBMS, OS. Josh mainly focus on DSA and on Tree Data Structure in interview.

Q1. 
Pair Sum in BST Problem Statement
Given a Binary Search Tree (BST) and a target value K, determine if there exist two unique elements in the BST such that their sum equals K.
Input:
An integer T, the nu...read more
Ans. 
The task is to check if there exist two unique elements in the given BST such that their sum is equal to the given target 'K'.
• Traverse the BST in-order and store the elements in a sorted array

• Use two pointers, one at the beginning and one at the end of the array

• Check if the sum of the elements at the two pointers is equal to the target 'K'

• If the sum is less than 'K', move the left pointer to the right

• If the sum is grea...read more
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Q2. 
Find Nodes at Distance K in a Binary Tree
Your task is to find all nodes that are exactly a distance K from a given node in an arbitrary binary tree. The distance is defined as the number of edges between ...read more
Ans. 
The task is to find all nodes in a binary tree that are at a distance K from a given node.
• Implement a function that takes the binary tree, target node, and distance K as input.

• Use a depth-first search (DFS) algorithm to traverse the tree and find the nodes at distance K.

• Keep track of the distance from the current node to the target node while traversing.

• When the distance equals K, add the current node to the result lis...read more
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Round duration - 20 minutes
Round difficulty - Easy

This was the simple 20 minutes round

Round duration - 180 min
Round difficulty - Hard

Q1. 
Longest Common Subsequence Problem Statement
Given two strings STR1 and STR2, determine the length of their longest common subsequence.
A subsequence is a sequence that can be derived from another sequen...read more
Ans. 
The problem involves finding the length of the longest common subsequence between two given strings.
• Use dynamic programming to solve the problem efficiently.

• Create a 2D array to store the lengths of common subsequences of substrings.

• Iterate through the strings to fill the array and find the length of the longest common subsequence.

• Example: For input STR1 = 'abcde' and STR2 = 'ace', the longest common subsequence is 'ac
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Q2. 
0/1 Knapsack Problem Statement
A thief is planning to rob a store and can carry a maximum weight of 'W' in his knapsack. The store contains 'N' items where the ith item has a weight of 'wi' and a value of...read more
Ans. 
Yes, the 0/1 Knapsack problem can be solved using dynamic programming with a space complexity of not more than O(W).
• Use a 1D array to store the maximum value that can be stolen for each weight capacity from 0 to W.

• Iterate through each item and update the array based on whether including the item would increase the total value.

• The final value in the array at index W will be the maximum value that can be stolen.
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Q3. 
K Largest Elements Problem Statement
You are given an unsorted array containing 'N' integers. Your task is to find the 'K' largest elements from this array and return them in non-decreasing order.
Input:
T...read more
Ans. 
Yes, the problem can be solved in less than O(N*log(N)) time complexity using the Quick Select algorithm.
• Implement Quick Select algorithm to find the Kth largest element in O(N) time complexity.

• Partition the array around a pivot element and recursively search in the left or right partition based on the position of the pivot.

• Once you find the Kth largest element, return all elements greater than or equal to it in non-de
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. 
Size of Largest BST in a Binary Tree
Given a binary tree with 'N' nodes, determine the size of the largest subtree that is also a Binary Search Tree (BST).
Explanation:
A Binary Search Tree (BST) is def...read more
Ans. 
Find the size of the largest BST subtree in a binary tree.
• Traverse the tree in a bottom-up manner to check if each subtree is a BST.

• Keep track of the size of the largest BST found so far.

• Recursively check if the current subtree is a BST and update the size accordingly.
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Q2. 
Matrix Chain Multiplication Problem
Given 'N' 2-dimensional matrices and an array ARR of length N + 1, where the first N integers denote the number of rows in each matrix and the last integer represents t...read more
Ans. 
Find the minimum number of multiplication operations required to multiply a series of matrices together.
• Use dynamic programming to solve this problem efficiently.

• Create a 2D array to store the minimum number of operations needed to multiply matrices.

• Iterate through different combinations of matrices to find the optimal solution.

• Consider the dimensions of the matrices to determine the number of operations required.

• Calcu...read more
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Q3. 
Rotate Linked List Problem Statement
Given a linked list consisting of 'N' nodes and an integer 'K', your task is to rotate the linked list by 'K' positions in a clockwise direction.
Example:
Input:
Li...read more
Ans. 
Rotate a linked list by K positions in a clockwise direction.
• Traverse the linked list to find the length and the last node.

• Connect the last node to the head to form a circular linked list.

• Find the new head by moving (length - K) steps from the last node.

• Break the circular list at the new head to get the rotated linked list.
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Round duration - 45 minutes
Round difficulty - Easy

Q1. 
Longest Palindromic Substring Problem Statement
You are provided with a string STR of length N. The task is to find the longest palindromic substring within STR. If there are several palindromic substring...read more
Ans. 
Given a string, find the longest palindromic substring within it.
• Iterate through the string and expand around each character to find palindromes

• Keep track of the longest palindrome found so far

• Return the longest palindromic substring
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Round duration - 60 Minutes
Round difficulty - Medium

This was the DSA questions round. There were 2 questions. and both were basic questions.

Q1. 
Check If Linked List Is Palindrome
Given a singly linked list of integers, determine if the linked list is a palindrome.
Explanation:
A linked list is considered a palindrome if it reads the same forwar...read more
Ans. 
Check if a given singly linked list of integers is a palindrome or not.
• Create a function to reverse the linked list.

• Use two pointers to find the middle of the linked list.

• Compare the first half of the linked list with the reversed second half to determine if it's a palindrome.
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Q2. 
Segregate Odd-Even Problem Statement
In a wedding ceremony at NinjaLand, attendees are blindfolded. People from the bride’s side hold odd numbers, while people from the groom’s side hold even numbers. For...read more
Ans. 
Rearrange a linked list such that odd numbers appear before even numbers while preserving the order.
• Create two separate linked lists for odd and even numbers

• Traverse the original list and append nodes to respective odd/even lists

• Combine the odd and even lists while maintaining the order

• Return the rearranged linked list
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Round duration - 90 Minutes
Round difficulty - Easy

This was a subjective round where we have to code HTML, CSS, and JS. We were not allowed to use any external editor and their editor was just plain notepad so we couldn't even see the output but still, we completed it. Everyone at my college passed this round.

Round duration - 10080 Minutes
Round difficulty - Easy

Round duration - 120 Minutes
Round difficulty - Medium

In this round, the interviewer asked me to turn on screen mirroring. And then he gave me 1 more design which I needed to create in front of him in the next 2 hours. In the previous round, the focus was on HTML and CSS but in this round, the major focus was on JS. You are allowed to use google but not copy-paste the whole code.

Round duration - 90 Minutes
Round difficulty - Hard

This was an online interview with one of their employees. My interview was taken by their front-end lead. She was very helpful during the interview. You are allowed to search for documentation.

Round duration - 90 Minutes
Round difficulty - Easy

This was also a front-end interview round. The interviewer was again very helpful and I was allowed to google.