300+ Jireh Software Solutions Interview Questions and Answers

Graph

• Use a graph data structure to represent people as nodes and friend relations as edges

• Each person can be represented as a node with their unique identifier

• Friend relations can be represented as directed edges between nodes

• This allows for efficient traversal and retrieval of friend connections

Custom stack with methods to return min and max elements

• Implement a stack using an array or linked list

• Track the minimum and maximum elements using additional variables

• Update the minimum and maximum variables during push and pop operations

• Implement methods to return the minimum and maximum elements

Given a tree and a node, print all ancestors of Node

• Start from the given node and traverse up the tree

• While traversing, keep track of the parent nodes

• Print the parent nodes as you traverse up until reaching the root

Explanation of useState, useEffect, useMemo, and useCallback hooks in React functional components.

• useState is used to manage state in functional components

• useEffect is used for handling side effects like data fetching, subscriptions, etc.

• useMemo is used for performance optimization by memoizing expensive calculations

• useCallback is used for memoizing functions to prevent unnecessary re-renders

• These hooks enhance functional components by providing state management, side effect ...read more

To add and manipulate elements in arrays using JavaScript, you can use array methods like splice() and slice().

• Use the splice() method to insert elements into an array at a specific index. For example, arr.splice(index, 0, 'watermelon') will insert 'watermelon' at the specified index without removing any elements.

• To manipulate elements in an array, you can use methods like splice() to remove elements or slice() to extract a portion of the array.

• Remember that arrays in JavaScr...read more

The for loop will run indefinitely without any condition to terminate it.

• The loop will continue executing until it is manually interrupted or the program crashes.

• This can lead to a program becoming unresponsive or consuming excessive resources.

• It is important to always include a condition in a for loop to control its execution.

Design and code a scheduler for allocating meeting rooms based on input of room counts and timestamps.

• Create a table with columns for room number, start time, and end time

• Use SQL queries to check for available slots and allocate rooms

• Consider edge cases such as overlapping meetings and room availability

• Use a loop to continuously check for available slots and allocate rooms

• Implement error handling for invalid input

Code to find median of datapoints in two sorted arrays

• Use binary search to find the median index

• Divide the arrays into two halves based on the median index

• Compare the middle elements of the two halves to determine the median

Different approaches for data cleaning include removing duplicates, handling missing values, correcting inconsistent data, and standardizing formats.

• Remove duplicates

• Handle missing values

• Correct inconsistent data

• Standardize formats

• Use statistical methods to identify outliers

• Check for data accuracy and completeness

• Normalize data

• Transform data types

• Apply data validation rules

Hyperparameters of XGBoost, Random Forest, and SVM can be tuned using techniques like grid search, random search, and Bayesian optimization.

• For XGBoost, important hyperparameters to tune include learning rate, maximum depth, and number of estimators.

• For Random Forest, important hyperparameters to tune include number of trees, maximum depth, and minimum samples split.

• For SVM, important hyperparameters to tune include kernel type, regularization parameter, and gamma value.

• Grid ...read more

Microservices are implemented using RESTful APIs and message brokers for asynchronous communication.

• RESTful APIs are used for synchronous communication between microservices.

• Message brokers like Kafka or RabbitMQ are used for asynchronous communication.

• Microservices communicate with each other using HTTP requests and responses.

• Each microservice has its own database and communicates with other microservices through APIs.

• Microservices are loosely coupled and can be developed an...read more

Setting up Redux store, connecting components, managing actions and reducers, and using middleware like Redux Thunk or Redux Saga for handling asynchronous actions.

• Setting up a Redux store involves creating a store with createStore() function from Redux, combining reducers with combineReducers(), and applying middleware like Redux Thunk or Redux Saga.

• Connecting components to the Redux store can be done using the connect() function from react-redux library, which allows compon...read more

The problem is to color a graph with two colors such that no two connected vertices have the same color.

• Use a graph coloring algorithm such as Depth First Search (DFS) or Breadth First Search (BFS).

• Start with an arbitrary vertex and color it with one color (e.g., blue).

• Color all its adjacent vertices with the other color (e.g., red).

• Continue this process for all connected components of the graph.

• If at any point, you encounter two adjacent vertices with the same color, it is n...read more

Hyperparameters are settings that control the behavior of machine learning algorithms.

• Hyperparameters are set before training the model.

• They control the learning process and affect the model's performance.

• Examples include learning rate, regularization strength, and number of hidden layers.

• Optimizing hyperparameters is important for achieving better model accuracy.

A program to simulate a race with 5 people using multithreading and determine the winner.

• Create a class for the race participants

• Implement the Runnable interface for each participant

• Use a thread pool to manage the threads

• Start all threads simultaneously

• Wait for all threads to finish

• Determine the winner based on the finishing time

An unique id for a massive parallel system can be generated using a combination of timestamp, machine id and a random number.

• Use a timestamp to ensure uniqueness

• Include a machine id to avoid collisions in a distributed system

• Add a random number to further increase uniqueness

• Consider using a UUID (Universally Unique Identifier) for simplicity

• Ensure the id generation algorithm is thread-safe

I follow the MVC design pattern as it separates concerns and promotes code reusability.

• MVC separates the application into Model, View, and Controller components.

• Model represents the data and business logic.

• View represents the user interface.

• Controller handles user input and updates the model and view accordingly.

• MVC promotes code reusability and maintainability.

• Example: Ruby on Rails framework follows MVC pattern.

Data is collected from various sources including databases, APIs, and user input.

• We have access to multiple databases where we can extract relevant data

• We use APIs to gather data from external sources such as social media platforms

• Users can input data through forms or surveys

• We also collect data through web scraping techniques

The sequence of execution of SQL codes is Select-From-Where-Group By-Having-Order By.

• Select: choose the columns to display

• From: specify the table(s) to retrieve data from

• Where: filter the data based on conditions

• Group By: group the data based on a column

• Having: filter the grouped data based on conditions

• Order By: sort the data based on a column

Code to describe database and columns from a table

• Use SQL SELECT statement to retrieve column names and data types

• Use DESC command to get table structure

• Use INFORMATION_SCHEMA.COLUMNS to get detailed information about columns

• Use SHOW CREATE TABLE to get table creation statement

Excel functions are pre-built formulas that perform calculations or manipulate data in a spreadsheet.

• Sum: adds up a range of numbers

• Sum if: adds up a range of numbers based on a specified condition

• Count: counts the number of cells in a range that contain numbers

• CountA: counts the number of cells in a range that are not empty

• Count Blanks: counts the number of empty cells in a range

Steps to fit a time series model

• Identify the time series pattern

• Choose a suitable model

• Split data into training and testing sets

• Fit the model to the training data

• Evaluate model performance on testing data

• Refine the model if necessary

• Forecast future values using the model

Mocking components in Jest for testing with props and named exports

• Use jest.mock() to mock components and their exports

• For handling props, use jest.fn() to create mock functions and pass them as props to the component being tested

• For named exports, use jest.mock() with a second argument to specify the module's exports

Design a Java-like Garbage Collector with minimal configurations.

• Choose a garbage collection algorithm (e.g. mark-and-sweep, copying, generational)

• Determine the heap size and divide it into regions (e.g. young, old, permanent)

• Implement a root set to keep track of live objects

• Set thresholds for garbage collection (e.g. occupancy, time)

• Implement the garbage collection algorithm and test for memory leaks

We implement multiple checks and balances to ensure payments are credited to the correct employee account.

• We verify the employee's account number and name before processing any payment.

• We implement a two-step verification process to ensure accuracy.

• We conduct regular audits to ensure all payments are correctly credited.

• We have a dedicated team to handle any payment discrepancies or errors.

• We provide training to employees on how to verify and confirm payment details.

• We use adv...read more

CSV files are plain text files that store tabular data, while Excel files are binary files that can contain multiple sheets and complex formatting.

• CSV files are simpler and more lightweight compared to Excel files.

• CSV files can be easily opened and edited using a text editor, while Excel files require specific software like Microsoft Excel.

• CSV files do not support formulas, macros, or formatting options like colors and fonts, while Excel files do.

• CSV files have a smaller file...read more

I have handled large amounts of data in my previous roles.

• I have experience handling terabytes of data in my previous role as a data analyst at XYZ company.

• I have worked with data from various sources such as databases, spreadsheets, and APIs.

• I have also used tools like SQL, Python, and Excel to manipulate and analyze data.

• I am comfortable working with both structured and unstructured data.

• I have experience cleaning and transforming data to make it usable for analysis.

I would use a hash table for efficient searching of a lot of data.

• Hash tables provide constant time complexity for search operations.

• They use a hash function to map keys to array indices, allowing for quick retrieval of data.

• Examples of hash table implementations include dictionaries in Python and HashMaps in Java.

Probability of raining given 3 friends with 2/3 truth probability saying it's raining.

• Use Bayes' theorem to calculate the probability

• P(Raining | All Friends Saying It's Raining) = P(All Friends Saying It's Raining | Raining) * P(Raining) / P(All Friends Saying It's Raining)

• P(All Friends Saying It's Raining | Raining) = 1

• P(Raining) = Prior probability of raining

• P(All Friends Saying It's Raining) = Probability of all friends saying it's raining

HAVING is used with GROUP BY to filter the results after grouping. WHERE is used to filter the results before grouping.

• HAVING is used with GROUP BY clause while WHERE is used with SELECT clause.

• HAVING is used to filter the results of aggregate functions while WHERE is used to filter individual rows.

• HAVING is used to filter the results after grouping while WHERE is used to filter the results before grouping.

• HAVING can only be used with aggregate functions while WHERE can be us...read more

Memoization is a technique used in programming to store the results of expensive function calls and return the cached result when the same inputs occur again.

• Memoization helps improve the performance of a function by caching its results.

• It is commonly used in dynamic programming to optimize recursive algorithms.

• Example: Memoizing a Fibonacci function to avoid redundant calculations.

Query to find the top five employee salaries

• Use the SELECT statement to retrieve the employee salaries

• Order the results in descending order using the ORDER BY clause

• Limit the results to the top five using the LIMIT clause

Stored procedures are precompiled SQL statements that can be reused and executed multiple times.

• Stored procedures improve performance by reducing network traffic and improving security.

• They can be used to encapsulate business logic and provide a consistent interface to the database.

• Stored procedures can also be used to simplify complex queries and transactions.

• Examples include procedures for inserting, updating, and deleting data, as well as generating reports and performing ...read more

Request flows in Spring Boot MVC, ways to instantiate a bean, and handling Java out-of-memory exception.

• Request flows in Spring Boot MVC: DispatcherServlet receives HTTP request, HandlerMapping maps request to appropriate controller, Controller processes request and returns response.

• Ways to instantiate a bean: Constructor injection, setter injection, and using the @Bean annotation.

• Handling Java out-of-memory exception: Analyze memory usage, increase heap size, optimize code, ...read more

Instagram uses a notification system to alert users when they are tagged and displays reels on the profile page based on user preferences and algorithms.

• Instagram uses a push notification system to alert users when they are tagged in a post or story.

• Reels are displayed on the profile page based on user engagement, preferences, and algorithms.

• The Explore page also suggests reels to users based on their interests and interactions on the platform.

Math.floor() is a method in JavaScript that rounds a number down to the nearest integer.

• Math.floor() returns the largest integer less than or equal to a given number.

• It is commonly used to convert a floating-point number to an integer.

• Example: Math.floor(3.9) returns 3.

A 5cm wooden cube is cut into smaller 1cm cubes. Determine the number of cubes with different numbers of painted sides.

• The original cube has 125 smaller cubes (5x5x5)

• Each smaller cube has 6 faces, so there are 750 faces in total

• The cubes on the edges have 3 painted sides, the ones on the corners have 3 painted sides, and the rest have 2 painted sides

• There are 8 cubes on the corners, 12 on the edges, and 105 in the middle

• There are 8 cubes with 3 painted sides, 36 with 2 painte...read more

A Promise is an object representing the eventual completion or failure of an asynchronous operation.

• A Promise is used to handle asynchronous operations in JavaScript.

• It represents a value that may be available now, or in the future.

• A polyfill for Promise can be implemented using the setTimeout function to simulate asynchronous behavior.

The interviewee was asked about word break, string to integer, and system design for an e-commerce app.

• Word break: Given a string and a dictionary of words, determine if the string can be segmented into a space-separated sequence of dictionary words.

• String to integer: Convert a string to an integer. Handle negative numbers and invalid inputs.

• System design e-commerce app: Design an e-commerce app with features like product listing, search, cart, checkout, payment, and order tr...read more

Reverse a linked list

• Iterate through the linked list and change the direction of the pointers

• Use three pointers to keep track of the previous, current, and next nodes

• Recursively reverse the linked list

Static, final, and abstract are keywords in Java used for different purposes.

• Static is used to create variables and methods that belong to the class rather than an instance of the class.

• Final is used to declare constants or to prevent a class, method, or variable from being overridden or modified.

• Abstract is used to create abstract classes and methods that cannot be instantiated and must be implemented by subclasses.

Ridge and LASSO are regularization techniques used in linear regression to prevent overfitting.

• Ridge adds a penalty term to the sum of squared errors, which shrinks the coefficients towards zero but doesn't set them exactly to zero.

• LASSO adds a penalty term to the absolute value of the coefficients, which can set some of them exactly to zero.

• The geometric interpretation of Ridge is that it adds a constraint to the size of the coefficients, which shrinks them towards the origi...read more

DSA questions on array and binary tree manipulation

• For printing pairs with target sum, use a hash table to store frequency of elements and check if complement exists

• For converting array to BST, use binary search to find the middle element and recursively build left and right subtrees

• For top view of binary tree, use a queue to traverse the tree level by level and store horizontal distance of nodes

• For minimum number of jumps, use dynamic programming to find minimum jumps requir...read more

Arrow functions do not have their own 'this' value, which is required in constructors.

• Arrow functions do not have a 'this' binding, so 'this' will refer to the parent scope.

• Constructors require 'this' to refer to the newly created object.

• Using arrow functions in constructors can lead to unexpected behavior and errors.

Moving payroll to Successfactors EC Payroll can have potential issues.

• Integration with other HR systems may be challenging

• Data migration can be complex and time-consuming

• Customization may be limited

• Training employees on new system may be required

• Costs associated with implementation and maintenance

• Compliance with local laws and regulations may be difficult

Payroll Control Center is a tool that streamlines payroll processing and provides real-time insights into payroll data.

• PCC allows for centralized management of payroll data and processes

• It provides real-time visibility into payroll data and analytics

• PCC can automate payroll processes and calculations

• It can integrate with other HR and finance systems

• PCC helps ensure compliance with payroll regulations and policies

Use two threads to print even and odd numbers in sequence

• Create two threads, one for printing even numbers and one for printing odd numbers

• Use synchronization mechanisms like mutex or semaphore to ensure numbers are printed in sequence

• Start both threads simultaneously and let them print numbers alternately

A trigger in SQL is a set of instructions that automatically executes in response to a specific event or action.

• Triggers can be used to enforce business rules, audit changes, or replicate data.

• They can be defined to execute before or after an INSERT, UPDATE, or DELETE statement.

• Triggers can also be nested, meaning one trigger can execute another trigger.

• Examples of triggers include sending an email notification when a new record is inserted, or updating a summary table when a...read more

For processing 10TB of file in Spark, consider allocating multiple executors with sufficient cores to maximize parallel processing.

• Allocate multiple executors to handle the large file size efficiently

• Determine the optimal number of cores per executor based on the available resources and workload

• Consider the memory requirements for each executor to avoid out-of-memory errors

• Adjust the configuration based on the specific requirements of the job and cluster setup