HashedIn by Deloitte Software Developer Interview Questions, Process, and Tips

Round duration - 120 minutes
Round difficulty - Medium

It was conducting in the afternoon, With great environment, and challenging questions

Q1. 
Find All Pairs Adding Up to Target
Given an array of integers ARR of length N and an integer Target, your task is to return all pairs of elements such that they add up to the Target.
Input:
The first line ...read more
Ans. 
Given an array of integers and a target, find all pairs of elements that add up to the target.
• Iterate through the array and for each element, check if the target - element exists in a hash set.

• If it exists, add the pair to the result. If not, add the element to the hash set.

• Handle cases where the same element is used twice to form a pair.

• Return (-1, -1) if no pair is found.
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Q2. 
Container With Most Water Problem Statement
Given a sequence of ‘N’ non-negative integers, A[1], A[2], ..., A[i], ..., A[N], where each number represents the height of a vertical line drawn at position 'i...read more
Ans. 
Find two lines to form a container with maximum water holding capacity.
• Use two pointers approach to find the maximum area by calculating the area between the lines and moving the pointers based on the height of the lines.

• Keep track of the maximum area found so far.

• The area is calculated as the minimum of the two line heights multiplied by the distance between the lines.

• Example: For input A = [1,8,6,2,5,4,8,3,7], the ma...read more
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Round duration - 60 minutes
Round difficulty - Medium

Coding + Core CS

Q1. 
Group Anagrams Problem Statement
Given an array or list of strings called inputStr, your task is to return the strings grouped as anagrams. Each group should contain strings that are anagrams of one anoth...read more
Ans. 
Group anagrams in an array of strings based on character frequency.
• Iterate through each string in the input array

• For each string, sort the characters and use the sorted string as a key in a hashmap to group anagrams

• Return the grouped anagrams as output
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Round duration - 60 minutes
Round difficulty - Medium

System Design + Core CS

Q1. Can you describe the design of a banking system?
Ans. 
A banking system is a software application that allows customers to perform financial transactions, manage accounts, and access banking services.
• The system should have user authentication and authorization mechanisms to ensure security.

• It should support various types of accounts such as savings, checking, and loans.

• The system should allow customers to deposit, withdraw, transfer funds, and view transaction history.

• It s...read more
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Round duration - 60 minutes
Round difficulty - Easy

Simple Basic HR Fitment

Round duration - 60 Minutes
Round difficulty - Medium

DSA based along with CS core subject questions. 
2 DSA question, one on String manipulation and another was on Array
Basic questions on Operating Systems

Q1. 
Remove Duplicates from String Problem Statement
You are provided a string STR of length N, consisting solely of lowercase English letters.
Your task is to remove all duplicate occurrences of characters i...read more
Ans. 
Remove duplicates from a string of lowercase English letters.
• Use a set to keep track of unique characters seen so far.

• Iterate through the string and add each character to the set if it hasn't been seen before.

• Construct a new string by appending characters that are not in the set.
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Q2. 
Maximum Subarray Sum Problem Statement
Given an array arr of length N consisting of integers, find the sum of the subarray (including empty subarray) with the maximum sum among all subarrays.
Explanation...read more
Ans. 
Find the sum of the subarray with the maximum sum among all subarrays in a given array.
• Iterate through the array and keep track of the maximum sum subarray seen so far.

• At each index, decide whether to include the current element in the subarray or start a new subarray.

• Update the maximum sum subarray if the current sum is greater than the previous maximum sum.
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Round duration - 50 minutes
Round difficulty - Easy

It was DSA based + Java based + Designing round. You can expect any question related to these topics depending upon Interviewer's choice and how you handle the round.

Q1. 
String Palindrome Verification
Given a string, your task is to determine if it is a palindrome considering only alphanumeric characters.
Input:
The input is a single string without any leading or trailing...read more
Ans. 
Determine if a given string is a palindrome considering only alphanumeric characters.
• Remove non-alphanumeric characters from the input string.

• Compare characters from start and end of the string to check for palindrome.

• Handle edge cases like empty string or single character input.
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Round duration - 20 Minutes
Round difficulty - Easy

The round here is called Fitment round i.e. to check how much you'll fit into HashedIn culture

Round duration - 90 minutes
Round difficulty - Medium

3 coding questions were there

Q1. 
Sort 0 1 2 Problem Statement
Given an integer array arr of size 'N' containing only 0s, 1s, and 2s, write an algorithm to sort the array.
Input:
The first line contains an integer 'T' representing the n...read more
Ans. 
Sort an array of 0s, 1s, and 2s in linear time complexity.
• Use three pointers to keep track of 0s, 1s, and 2s while iterating through the array.

• Swap elements based on the values encountered to sort the array in-place.

• Time complexity should be O(N) and space complexity should be O(1).
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Q2. 
Longest Increasing Subsequence Problem Statement
Given an array of integers with 'N' elements, determine the length of the longest subsequence where each element is greater than the previous element. This...read more
Ans. 
Find the length of the longest strictly increasing subsequence in an array of integers.
• Use dynamic programming to solve this problem efficiently.

• Initialize an array to store the length of the longest increasing subsequence ending at each index.

• Iterate through the array and update the length of the longest increasing subsequence for each element.

• Return the maximum value in the array as the result.
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Round duration - 60 Minutes
Round difficulty - Medium

2 coding were asked

Q1. 
Minimum Number of Platforms Needed Problem Statement
You are given the arrival and departure times of N trains at a railway station for a particular day. Your task is to determine the minimum number of pl...read more
Ans. 
Determine the minimum number of platforms needed at a railway station based on arrival and departure times of trains.
• Sort the arrival and departure times in ascending order.

• Use two pointers to keep track of overlapping schedules.

• Increment the platform count when a new train arrives before the previous one departs.

• Return the maximum platform count needed.
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Round duration - 60 Minutes
Round difficulty - Medium

2 coding questions

Q1. 
Lowest Common Ancestor (LCA) Problem Statement
Understanding the concept of Lowest Common Ancestor (LCA) in graph theory and computer science is essential.
Consider a rooted tree ‘T’ containing ‘N’ nodes...read more
Ans. 
The Lowest Common Ancestor (LCA) problem involves finding the lowest node in a tree that is an ancestor of two given nodes.
• LCA is the lowest node in a tree that is an ancestor of both given nodes.

• The tree is rooted at node 1 for each test case.

• Paths from each node to the root are considered to find the LCA.

• Constraints include the number of test cases, nodes, queries, and node values.

• Time limit for the solution is 1 sec
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Round duration - 15 Minutes
Round difficulty - Easy

Basic questions like "tell me about family members and their occupation", "why hashedin" are asked.

Round duration - 60 minutes
Round difficulty - Medium

Q1. 
Four Sum Problem Statement
You are provided with an array/list 'ARR' consisting of 'N' integers and an integer 'TARGET'. The task is to determine if there exist four distinct numbers in 'ARR' such that th...read more
Ans. 
The task is to determine if there exist four distinct numbers in an array that sum up to a given target value.
• Iterate through all possible combinations of four distinct numbers in the array.

• Use a nested loop to check all combinations efficiently.

• Keep track of the sum of each combination and compare it with the target value.

• Return 'Yes' if a valid combination is found, otherwise return 'No'.
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Round duration - 50 minutes
Round difficulty - Medium

Q1. 
Detect and Remove Loop in Linked List
For a given singly linked list, identify if a loop exists and remove it, adjusting the linked list in place. Return the modified linked list.
Expected Complexity:
A...read more
Ans. 
Detect and remove loop in a singly linked list in place with O(n) time complexity and O(1) space complexity.
• Use Floyd's Tortoise and Hare algorithm to detect the loop in the linked list.

• Once the loop is detected, find the start of the loop using the same algorithm.

• Adjust the pointers to remove the loop and return the modified linked list.

• Example: For input 5 2 and elements 1 2 3 4 5, output should be 1 2 3 4 5.
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Q2. 
Lowest Common Ancestor in a BST Problem Statement
You're provided with a Binary Search Tree (BST) containing 'N' nodes with integer values and two specific nodes, 'P' and 'Q'.
Your task is to identify th...read more
Ans. 
Find the lowest common ancestor of two nodes in a Binary Search Tree.
• Traverse the BST from the root to find the LCA of the given nodes.

• Compare the values of the nodes with the values of P and Q to determine the LCA.

• Handle cases where one node is the ancestor of the other or when one of the nodes is the root.

• Use recursion to efficiently find the LCA in the BST.

• Consider edge cases such as when the nodes are not present i
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Round duration - 120 Minutes
Round difficulty - Medium

Q1. 
Triplets with Given Sum Problem
Given an array or list ARR consisting of N integers, your task is to identify all distinct triplets within the array that sum up to a specified number K.
Explanation:
A t...read more
Ans. 
The task is to find all distinct triplets in an array that sum up to a specified number.
• Iterate through all possible triplets using three nested loops.

• Check if the sum of the triplet equals the target sum.

• Print the triplet if found, else print -1.
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Q2. Can you describe a situation where you were given a schema and asked to write SQL queries based on it?
Ans. 
Yes, I was given a schema and asked to write SQL queries based on it.
• I was given a schema for a database that included tables, columns, and relationships between them.

• I had to write SQL queries to retrieve specific data from the database based on the schema provided.

• For example, I was asked to write a query to retrieve all customers who made a purchase in the last month.

• I had to understand the schema to correctly write...read more
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Round duration - 20 Minutes
Round difficulty - Easy

Q1. Can you tell me about yourself and what new things you did during the lockdown?
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