Quinbay Software Developer Intern Interview Questions and Answers

Round duration - 90 minutes
Round difficulty - Medium

They share doc file link which consist of 5 programming questions

Q1. 
Reverse Words in a String: Problem Statement
You are given a string of length N. Your task is to reverse the string word by word. The input may contain multiple spaces between words and may have leading o...read more
Ans. Brute force
• Create a String ans to store the reversed string.
• Initialize a variable i to 0 and iterate the whole string through a while loop.
• Skip initial spaces by just incrementing i.
• Create a String that will store the current word.
• Add the currentword and space at the beginning of ans.
• After traversing the whole string, check if the length of ans is greater than 0 then return ans after removing the last space otherwise r...read more
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Q2. 
Fibonacci Membership Check
Given an integer N, determine if it is a member of the Fibonacci series. Return true if the number is a member of the Fibonacci series, otherwise return false.
Fibonacci Series...read more
Ans. Space Complexity: Explanation: Time Complexity: Explanation:
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Q3. 
Maximum Difference Problem Statement
Given an array ARR of N elements, your task is to find the maximum difference between any two elements in ARR.
If the maximum difference is even, print EVEN; if it is...read more
Ans. Find Max And Min
We will iterate over ARR and find the MAX and MIN of the ARR. And if the MAX - MIN is odd the return “ODD” else return "EVEN". 
The algorithm will be-
1. MAX = -1, MIN= 10 ^ 9 + 1
2. For VAL in ARR.
   1. If MAX < VAL
      1. MAX = VAL
   2. If MIN > VAL
      1. MIN = VAL
3. IF (MAX-MIN) % 2
   1. Return ODD
4. ELSE
   1. Return EVEN
Space Complexity: O(1)Explanation:
O(1).
 
Since constant space is used.
Time Complexity: O(n)Explanation:
O(N), where N ...read more
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Q4. 
Remainder When Divided By 11 Problem Statement
Determine the remainder when a given number, 'N' in the form of a string, is divided by 11.
Input:
The first line contains an integer 'T' denoting the numb...read more
Ans. Using Modulo Property
1. Since the number is very large we can not simply calculate N % 11.
2. Now, any number say 256 % 11 can be calculated as (25*10 + 6)%11. Which in turn can be calculated as (( 25*10)%11+ 6)%11 or ( (25%11)*10 + 6)%11. Similarly 25%11 can be calculated as (2*10+5)%11. Therefore , 256 %11 can be finally calculated as ( ( (2*10 + 5)%11 )*10 + 6)%11.
3. So, the idea is to store the number N in string Str.
4. Take a ...read more
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Round duration - 60 minutes
Round difficulty - Medium

In this round interviewer asked me to solve 3 programming questions.

Q1. 
Selection Sort Algorithm
Selection sort is a sorting technique that works by repeatedly finding the minimum element (considering ascending order) from the unsorted part and placing it at the beginning of ...read more
Ans. Selection Sort Approach
Selection sort is a standard sorting algorithm that uses nested loops to find all the minimum elements in the array in each iteration and swap them with the starting element of the unsorted region of the array.
 
Steps :
• Use a minValue variable to find the index of the minimum element of the array.
• Use a loop to iterate over all the elements of the array.
• Use a nested loop to find the minimum ele...read more
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Q2. 
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. Space Complexity: Explanation: Time Complexity: Explanation:
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Q3. 
Star Pattern Problem Statement
Display the star pattern for a given positive integer N.
Example:
Input:
N = 4
Output:
   *
  ***
 *****
*******
 
Explanation:
The dots in the image represent spaces. Al...read more
Ans. Space Complexity: Explanation: Time Complexity: Explanation:
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Round duration - 60 minutes
Round difficulty - Easy

This was the HR round. They asked me simple HR questions and 1 coding question.

Q1. 
Character Counting Challenge
Create a program that counts and prints the total number of specific character types from user input. Specifically, you need to count lowercase English alphabets, numeric digi...read more
Ans. Space Complexity: O(1)Explanation: Time Complexity: O(1)Explanation:
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Aptitude test consisted of around 45 MCQs from basic topics like C, C++, OOPS

2nd round had 3 medium level (Leetcode) questions and 1 output question: 1. Level order traversal, 2. count zeros(not sure), 3. Linked List traversal related.

Round duration - 45 minutes
Round difficulty - Easy

There were around 20 mcq's on Aptitude.
1 Coding Question

Q1. 
Sum of Maximum and Minimum Elements Problem Statement
Given an array ARR of size N, your objective is to determine the sum of the largest and smallest elements within the array.
Follow Up:
Can you achie...read more
Ans. 
First I initialized two variables max and min.
and traverse the array to find max and min.
then return the sum of max and min.
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Round duration - 60 minutes
Round difficulty - Easy

Q1. 
Design a Constant Time Data Structure
Create a data structure that maintains mappings between keys and values, supporting the following operations in constant time:
1. INSERT(key, value): Add or update t...read more
Ans. Array Approach - Separate Chaining
Approach:
HashMap is the data structure used to store key-value pairs, where the average retrieval time for get() and insert() operations is constant i.e. O(1).
 
Hashmap uses the array of Singly Linked List internally.
 
The array is called the buckets and at every bucket(i-th index of the array) holds a pointer to head of the Singly Linked List. 
Every Linked List Node has f...read more
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Round duration - 75 minutes
Round difficulty - Medium

Round held at 12 noon. There were 2 interviewers

Q1. 
Zig-Zag Array Rearrangement
You are provided with an array of distinct elements, and your task is to rearrange the array elements in a zig-zag manner. Specifically, for every odd index i, the element ARR[...read more
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Q2. 
Sum Root to Leaf Path Problem
You are given an arbitrary binary tree consisting of N nodes where each node is associated with an integer value from 1 to 9. Each root-to-leaf path in the tree represents a ...read more
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Round duration - 120 minutes
Round difficulty - Easy

Round held at 4pm. There were 2 interviewers

Q1. 
Reverse Linked List in Groups of K
You are provided with a linked list containing 'N' nodes and an integer 'K'. The task is to reverse the linked list in groups of size K, which means reversing the nodes ...read more
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Q2. 
Nodes at Distance K from a Given Node
Given an arbitrary binary tree, a specified node within the tree, and an integer 'K', find all nodes that are exactly 'K' distance away from the specified node. Retur...read more
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Round duration - 60 minutes
Round difficulty - Medium

Timing was late. Environment was good.

Q1. 
Dijkstra's Shortest Path Problem
Given an undirected graph with ‘V’ vertices (labeled 0, 1, ... , V-1) and ‘E’ edges, where each edge has a weight representing the distance between two connected nodes (X,...read more
Ans. Using Adjacency Matrix
The idea is to maintain two arrays, one stores the visited nodes, and the other array stores the distance (element at index ‘i’ denotes the distance from node 0 to node ‘i’). We pick an unvisited minimum distance vertex, then update the distance of all its adjacent vertices considering the path from source to an adjacent vertex to pass through the picked minimum distance vertex. Repeat the process...read more
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Q2. 
Spiral Matrix Path Problem Statement
Given a N x M matrix of integers, print the spiral order of the matrix.
Input:
The input starts with an integer 'T' representing the number of test cases. Each test ...read more
Ans. Recursive
For each boundary, we will use the 4 loops. Now the problem is reduced to print the remaining submatrix which is handled with the help of recursion. Keep track of new dimensions(rows and columns) of the current submatrix which are passed with the help of parameters in each recursion call.
 
Algorithm:
 
spiralPrint(matrix[][], startingRow, startingCol, endingRow, endingCol):
• Check for base cases, i.e. if ...read more
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Q3. 
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. Dynamic Programming
Approach: In the Dynamic programming we will work considering the same cases as mentioned in the recursive approach. In a DP[][] table let’s consider all the possible weights from ‘1’ to ‘W’ as the columns and weights that can be kept as the rows. 
The state DP[i][j] will denote maximum value of ‘j-weight’ considering all values from ‘1 to ith’. So if we consider ‘wi’ (weight in ‘ith’ row) we can...read more
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Round duration - 75 minutes
Round difficulty - Medium

It was a coding round.

Q1. 
Multiply Linked Lists Problem Statement
Your task is to multiply two numbers represented as linked lists and return the resultant multiplied linked list.
Explanation:
The multiplied list should be a lin...read more
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Q2. 
Binary Tree Diameter Problem Statement
Given a binary tree, determine the length of its diameter. The diameter is defined as the longest path between any two end nodes in the tree. The path's length is re...read more
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Round duration - 70 mintues
Round difficulty - Medium

It was an online coding round.

Q1. 
Add Two Numbers Represented by Linked Lists
Your task is to find the sum list of two numbers represented by linked lists and return the head of the sum list.
Explanation:
The sum list should be a linked...read more
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Q2. 
Buy and Sell Stock Problem Statement
Imagine you are Harshad Mehta's friend, and you have been given the stock prices of a particular company for the next 'N' days. You can perform up to two buy-and-sell ...read more
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Q3. 
Is Height Balanced Binary Tree Problem Statement
Determine if the given binary tree is height-balanced. A tree is considered height-balanced when:
1. The left subtree is balanced.
2. The right subtree is bala...read more
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Round duration - 90 minutes
Round difficulty - Medium

In this round, three questions were asked and all of them were based on DSA.

Q1. 
Sum Root to Leaf Numbers
You are given an arbitrary binary tree consisting of N nodes, each associated with an integer value from 1 to 9. Each root-to-leaf path can be considered a number formed by concat...read more
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Q2. 
Maximum Non-Adjacent Subsequence Sum
Given an array of integers, determine the maximum sum of a subsequence without choosing adjacent elements in the original array.
Input:
The first line consists of an...read more
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Q3. 
Rearrange Linked List Problem Statement
Given a singly linked list in the form 'L1' -> 'L2' -> 'L3' -> ... 'Ln', your task is to rearrange the nodes to the form 'L1' -> 'Ln' -> 'L2' -> '...read more
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Round duration - 120 minutes
Round difficulty - Medium

In this round, three questions were asked and all of them were based on DSA and a little bit about projects.

Q1. 
Minimum Jumps Problem Statement
Bob and his wife are in the famous 'Arcade' mall in the city of Berland. This mall has a unique way of moving between shops using trampolines. Each shop is laid out in a st...read more
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Q2. 
N Queens Problem
Given an integer N, find all possible placements of N queens on an N x N chessboard such that no two queens threaten each other.
Explanation:
A queen can attack another queen if they ar...read more
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Q3. 
Flatten Binary Tree to Linked List
Transform a binary tree with integer values into a linked list by ensuring the linked list's nodes follow the pre-order traversal order of the binary tree.
Explanation:
...read more
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Round duration - 20 mintues
Round difficulty - Easy

It was on the next day of the last technical round, I was on the same site as the technical interview round.