Headout Reservation & Ticketing Executive Interview Questions and Answers

Round duration - 60 minutes
Round difficulty - Easy

Technical round with 3 problems based on DSA and Algorithms.

Q1. 
Smallest Integer Not Representable as Subset Sum
Given a non-decreasing sorted array ARR of N positive numbers, determine the smallest positive integer that cannot be expressed as the sum of elements from...read more
Ans. 
Find the smallest positive integer that cannot be expressed as the sum of elements from any proper subset of a given array.
• Sort the array in non-decreasing order.

• Iterate through the array and keep track of the smallest sum that can be formed.

• If the next element in the array is greater than the current sum + 1, then the answer is the current sum + 1.

• Return the answer as the smallest integer not representable as a subset
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Q2. 
Reverse Linked List Problem Statement
Given a singly linked list of integers, return the head of the reversed linked list.
Example:
Initial linked list: 1 -> 2 -> 3 -> 4 -> NULL
Reversed link...read more
Ans. 
Reverse a singly linked list of integers and return the head of the reversed linked list.
• Iterate through the linked list and reverse the pointers to point to the previous node instead of the next node.

• Use three pointers to keep track of the current, previous, and next nodes while reversing the linked list.

• Update the head of the reversed linked list to be the last node encountered during the reversal process.
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Q3. 
Smallest Window Problem Statement
Given two strings S and X containing random characters, the task is to find the smallest substring in S which contains all the characters present in X.
Input:
The first...read more
Ans. 
The task is to find the smallest substring in string S which contains all the characters present in string X.
• Iterate through string S and keep track of characters in X using a hashmap

• Use two pointers to maintain a sliding window and find the smallest window containing all characters in X

• Return the smallest window found
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Round duration - 60 minutes
Round difficulty - Easy

Technical round with questions based on OOPS and Angular.

Q1. What are the different OOP concepts?
Ans. 
OOP concepts include inheritance, encapsulation, polymorphism, and abstraction.
• Inheritance allows a class to inherit properties and behavior from another class.

• Encapsulation restricts access to certain components of an object, protecting its integrity.

• Polymorphism allows objects to be treated as instances of their parent class.

• Abstraction hides the complex implementation details of an object and only shows the necessar
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Round duration - 60 minutes
Round difficulty - Easy

Questions based on System Design, ajax, jquery were asked.

Q1. How would you design a traffic light system?
Ans. 
Designing a traffic light system involves creating a system that controls the flow of traffic at intersections.
• Divide the traffic light system into three main lights: red, yellow, and green.

• Implement timers to control the duration of each light.

• Include sensors to detect the presence of vehicles and pedestrians.

• Consider implementing a pedestrian crossing signal.

• Integrate a central control system to coordinate the timing
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Q2. How does AJAX work?
Ans. 
AJAX allows for asynchronous communication between client and server without needing to reload the entire page.
• AJAX stands for Asynchronous JavaScript and XML.

• It allows for sending and receiving data from a server without reloading the entire page.

• AJAX uses XMLHttpRequest object to make requests to the server.

• It can update parts of a web page without requiring a full page reload.

• Commonly used in web applications to pro
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Q3. What is the difference between AngularJS and jQuery?
Ans. 
AngularJS is a full-fledged MVC framework for building dynamic web applications, while jQuery is a lightweight library for DOM manipulation and event handling.
• AngularJS is a full-fledged MVC framework, providing features like two-way data binding, dependency injection, and routing.

• jQuery is a lightweight library primarily used for DOM manipulation and event handling.

• AngularJS is suitable for building single-page applic...read more
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Round duration - 90 minutes
Round difficulty - Medium

Q1. 
Rotate Matrix Right K Times
You are given a matrix MAT of size 'N' * 'M', where 'N' is the number of rows and 'M' is the number of columns, along with a positive integer 'K'. Your task is to rotate the ma...read more
Ans. 
Rotate a matrix to the right 'K' times by shifting each column to the right 'K' times.
• Iterate 'K' times to perform right rotation on the matrix

• Shift each column to the right by one position in each rotation

• Handle wrapping around the matrix when shifting columns

• Return the matrix elements row-wise after 'K' rotations
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Q2. 
Word Search Problem Statement
Given a two-dimensional grid of size N x M consisting of upper case characters and a string 'WORD', determine how many times the 'WORD' appears in the grid.
The 'WORD' can b...read more
Ans. 
Count how many times a given word appears in a 2D grid by moving in any of the eight possible directions.
• Iterate through each cell in the grid and check if the word can be formed starting from that cell in any of the eight directions.

• Use recursion to explore all possible paths from a starting cell to form the word.

• Keep track of visited cells to avoid revisiting the same cell in the same path.

• Return the count of how man
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Round duration - 75 minutes
Round difficulty - Medium

Interview started with an introduction and walk through the resume for first 5 minutes. After that, interview asked few coding questions.

Q1. 
Problem Statement: Largest Island
You are provided with a non-empty grid consisting of only 0s and 1s. Your task is to determine the maximum area of an island within the given grid.
An island consists of a...read more
Ans. 
Find the maximum area of an island in a grid of 0s and 1s.
• Iterate through the grid and perform depth-first search (DFS) to find connected 1s.

• Keep track of the area of each island found and return the maximum area.

• Consider all four directions (horizontal, vertical, and diagonal) while exploring the island.

• Handle edge cases like grid boundaries and already visited cells during DFS.

• If no island is present, return 0 as the
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Q2. 
Pythagorean Triplet Problem
Determine if there exists a Pythagorean triplet within a given array of integers. A Pythagorean triplet consists of three numbers, x, y, and z, such that x^2 + y^2 = z^2.
Expl...read more
Ans. 
Check if there exists a Pythagorean triplet in a given array of integers.
• Iterate through all possible triplets in the array and check if they form a Pythagorean triplet.

• Use a nested loop to generate all possible combinations of three numbers from the array.

• Check if the sum of squares of two numbers is equal to the square of the third number.
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Q3. 
Top View of Binary Tree Problem Statement
Given a Binary Tree of integers, you are tasked with finding the top view of the binary tree. The top view is the set of nodes visible when the tree is viewed fro...read more
Ans. 
Find the top view of a Binary Tree by returning a list of visible nodes when viewed from the top.
• Traverse the Binary Tree in level order and keep track of the horizontal distance of each node from the root.

• Use a map to store the nodes at each horizontal distance, and only keep the topmost node for each horizontal distance.

• Return the values of the topmost nodes in the map as the top view of the Binary Tree.
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Round duration - 90 minutes
Round difficulty - Medium

This round was focused on DSA along with short discussion on computer science fundamentals. For coding problems, I was asked to code the first problem only. For others, had to discuss the approach only. For computer science fundamentals, discussion on OOPS. Differences between process and threads were discussed.

Q1. 
Fixing a Swapped Binary Search Tree
Given a Binary Search Tree (BST) where two nodes have been swapped by mistake, your task is to restore or fix the BST without changing its structure.
Input:
The first...read more
Ans. 
Restore a Binary Search Tree by fixing two swapped nodes without changing its structure.
• Identify the two nodes that are swapped by mistake in the BST.

• Swap the values of the two identified nodes to restore the BST.

• Perform an in-order traversal of the BST to verify the correct restoration.

• Ensure no extra space other than the recursion stack is used for the solution.
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Q2. 
Implement Stack with Linked List
Your task is to implement a Stack data structure using a Singly Linked List.
Explanation:
Create a class named Stack which supports the following operations, each in O(1...read more
Ans. 
Implement a Stack data structure using a Singly Linked List with operations like getSize, isEmpty, push, pop, and getTop in O(1) time.
• Create a class named Stack with methods for getSize, isEmpty, push, pop, and getTop.

• Use a Singly Linked List to store the elements of the stack.

• Ensure that each operation runs in constant time O(1).

• Handle edge cases like empty stack appropriately.

• Test the implementation with sample queri
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Round duration - 90 minutes
Round difficulty - Medium

Coding question of medium level difficulty, from DP. 
18 MCQs were core CSE related concepts e.g: OS, OOPs, DBMS, Networking
Time was 90 minutes.

Q1. 
Minimum Cost to Destination
You are given an NxM matrix consisting of '0's and '1's. A '1' signifies that the cell is accessible, whereas a '0' indicates that the cell is blocked. Your task is to compute ...read more
Ans. 
Find the minimum cost to reach a destination in a matrix with blocked cells.
• Use Breadth First Search (BFS) algorithm to explore all possible paths from the starting point to the destination.

• Keep track of the cost incurred at each cell and update it as you move through the matrix.

• Return the minimum cost to reach the destination or -1 if it is unreachable.
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Round duration - 30 minutes
Round difficulty - Medium

It was an one-to-one interview. It checks your problem solving ability and a few OOPs, OS, DBMS etc concepts. Coding questions were related to array, queue and DP.

Q1. 
Triangle Formation Using Array Elements
Given an integer array/list ARR of length 'N', determine if it is possible to form at least one non-degenerate triangle using the values of the array as the sides o...read more
Ans. 
Determine if it is possible to form a non-degenerate triangle using array elements as sides.
• Check if the sum of any two sides is greater than the third side for all combinations of sides.

• If the above condition is met for any combination, return true; otherwise, return false.
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Q2. 
Maximum Sum of Non-Adjacent Elements
You are given an array/list of integers. The task is to return the maximum sum of a subsequence such that no two elements in the subsequence are adjacent in the given ...read more
Ans. 
Find the maximum sum of non-adjacent elements in an array.
• Use dynamic programming to keep track of the maximum sum at each index, considering whether to include the current element or not.

• At each index, the maximum sum can be either the sum excluding the current element or the sum including the current element but excluding the previous element.

• Iterate through the array and update the maximum sum accordingly.

• Example: F...read more
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Round duration - 45 minutes
Round difficulty - Easy

It was also a problem solving round. However after coding questions, they also asked CSE conceptual questions.

Q1. 
Sum Tree Conversion
Convert a given binary tree into its sum tree. In a sum tree, every node's value is replaced with the sum of its immediate children's values. Leaf nodes are set to 0. Finally, return th...read more
Ans. 
Convert a binary tree into a sum tree by replacing each node's value with the sum of its children's values. Return preorder traversal.
• Traverse the tree in a bottom-up manner, starting from the leaf nodes.

• For each node, update its value to the sum of its children's values.

• Set leaf nodes to 0.

• Return the preorder traversal of the modified tree.
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Q2. What are the core concepts of indexing in Database Management Systems (DBMS)?
Ans. 
Core concepts of indexing in DBMS include types of indexes, benefits of indexing, and factors affecting index performance.
• Types of indexes: B-tree, Hash, Bitmap, etc.

• Benefits of indexing: Faster data retrieval, improved query performance, reduced disk I/O.

• Factors affecting index performance: Selectivity, clustering factor, index fragmentation.

• Examples: Creating an index on a column in a table to speed up search queries
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Round duration - 90 Minutes
Round difficulty - Easy

Q1. 
Position of Right Most Set Bit
Determine the position of the rightmost set bit in the binary representation of a given number N.
Input:
T: Number of test cases
N: An integer for which the position of the...read more
Ans. 
Find the position of the rightmost set bit in a given number's binary representation.
• Convert the number to binary representation.

• Find the position of the rightmost set bit by counting from right to left.

• Return the position of the rightmost set bit.
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. 
Water Jug Problem Statement
You have two water jugs with capacities X and Y liters respectively, both initially empty. You also have an infinite water supply. The goal is to determine if it is possible to...read more
Ans. 
The Water Jug Problem involves determining if a specific amount of water can be measured using two jugs of different capacities.
• Start by considering the constraints and limitations of the problem.

• Think about how the operations allowed can be used to reach the target measurement.

• Consider different scenarios and test cases to understand the problem better.

• Implement a function that can determine if the target measurement
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Round duration - 60 Minutes
Round difficulty - Medium

It was 1 hour long and was asked to pass all the test cases.

Q1. System Design with basic of OOP and OS
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There were some aptitude question, Pandas question, SQL queries.

Q1. Use SQL to filter duplicate entries.
Ans. 
Use SQL query with DISTINCT keyword to filter duplicate entries.
• Use SELECT DISTINCT column_name FROM table_name;

• DISTINCT keyword removes duplicate values from the result set.

• For example, SELECT DISTINCT name FROM employees;

• You can also use GROUP BY clause to eliminate duplicates.
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Q2. Questions on Excel Shorcuts.
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Q1. SQL Questions are asked, learn joins and aggregate functions
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Simple Case Study was discussed

Q1. Company fit check and salary expectations
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