8000+ Software Engineer Interview Questions and Answers

Four people with different crossing times need to cross a bridge with a torch. Only two can cross at a time. What is the least time taken?

• Person A and B cross first, taking 2 minutes

• A goes back with the torch, taking 1 minute

• C and D cross together, taking 10 minutes

• B goes back with the torch, taking 2 minutes

• A and B cross together, taking 2 minutes

• Total time taken is 17 minutes

You need to take 36 turns to find a perfect pair.

• You need to pick 19 gloves to ensure a perfect pair.

• The worst case scenario is picking 18 white gloves and then the 19th glove is black.

• In that case, you need to pick 17 more gloves to find a black one and complete the pair.

The interview questions cover topics like encapsulation, inheritance, constructors, method overloading, overriding, exception handling, and hobbies.

• Encapsulation is the process of hiding the internal details of an object and providing access through methods.

• Inheritance is a mechanism in which one class inherits the properties and behaviors of another class.

• A constructor is a special method used to initialize objects.

• Method overloading is the ability to define multiple methods...read more

A puzzle where 100 people shoot the person in front of them until only one person remains.

• Each person shoots the person in front of them and hands the gun to the next to next person.

• This continues until only one person remains.

• The last person standing is the one who was not shot by anyone.

Cut the cake in half horizontally, then vertically, and finally cut each half diagonally.

• Cut the cake horizontally through the middle.

• Cut the cake vertically through the middle.

• Cut each half diagonally from corner to corner.

• Ensure each cut is made symmetrically to get 8 equal pieces.

• Example: https://www.youtube.com/watch?v=ZdGmuCJzQFo

A stack is a LIFO data structure while a queue is a FIFO data structure.

• Stack: Last In First Out (LIFO), used in undo-redo functionality, backtracking, and recursion.

• Queue: First In First Out (FIFO), used in scheduling, buffering, and breadth-first search.

• Example: A stack can be used to store the history of visited web pages while a queue can be used to manage incoming requests in a web server.

The task is to split a binary string into beautiful substrings with equal number of 0's and 1's.

• Count the number of 0's and 1's in the string.

• Iterate through the string and split it into beautiful substrings whenever the count of 0's and 1's becomes equal.

• Return the maximum number of beautiful substrings that can be formed.

• If it is not possible to split the string into beautiful substrings, return -1.

Given a string and an array of indices, reverse substrings based on the indices to obtain the final string.

• Iterate through the array of indices and reverse the substrings accordingly

• Ensure the range specified by each index is non-empty

• Return the final string after all operations are completed

Calculate and print the factorial of a given integer N.

• Iterate from 1 to N and multiply each number to calculate factorial.

• Handle edge cases like N=0 or N=1 separately.

• Use recursion to calculate factorial efficiently.

• Consider using dynamic programming to optimize factorial calculation.

• Ensure to handle large values of N to prevent overflow issues.

Iterative Waterfall model was introduced to address the limitations of the traditional Waterfall model.

• Iterative Waterfall model allows for feedback and changes during the development process.

• It breaks down the development process into smaller, more manageable stages.

• It reduces the risk of project failure by identifying and addressing issues early on.

• It allows for better collaboration between developers and stakeholders.

• Examples include Rational Unified Process (RUP) and Agil...read more

Calculate the Nth element of a modified Fibonacci series given the first two numbers and N, with the result modulo 10^9 + 7.

• Implement a function to calculate the Nth element of the series using the Fibonacci rule f(x) = f(x - 1) + f(x - 2)

• Return the answer modulo 10^9 + 7 due to the possibility of a very large result

• The series starts with the first two numbers X and Y, and the position N in the series

Determine if it is possible to divide a string into three non-empty substrings where one is a substring of the other two.

• Check if any substring of the string is a substring of the other two substrings.

• Iterate through all possible divisions of the string into three non-empty substrings.

• Use two pointers to find all possible substrings efficiently.

Find all pairs of elements in an array that add up to a given target.

• Iterate through the array and use a hashmap to store the difference between the target and current element.

• Check if the current element exists in the hashmap, if so, print the pair.

• If no pair is found, print (-1, -1).

Sort a list of people by their cities and states.

• Use a sorting algorithm like quicksort or mergesort.

• Create a custom comparator function that compares the city and state of each person.

• If two people belong to the same city and state, sort them by their names.

• Example: [{name: 'John', city: 'New York', state: 'NY'}, {name: 'Jane', city: 'Boston', state: 'MA'}]

• Example output: [{name: 'Jane', city: 'Boston', state: 'MA'}, {name: 'John', city: 'New York', state: 'NY'}]

Implement a function to compress a string by replacing consecutive characters with the character followed by the count of repetitions.

• Iterate through the input string and keep track of consecutive characters and their counts

• Replace consecutive characters with the character followed by the count of repetitions if count is greater than 1

• Return the compressed string

Developing a real-time chat application with high scalability and low latency.

• Designing a distributed architecture to handle a large number of concurrent users.

• Implementing efficient data synchronization between multiple servers.

• Optimizing network communication to minimize latency.

• Ensuring data consistency and reliability in a distributed environment.

The error handling function copies elements from q2 back to q1 in case of an error.

• Use q_len() to get the length of the queues

• Use q_insert() and q_remove() to manipulate the queues

• Iterate through q2 and use q_insert() to copy elements back to q1

Given two numbers represented as arrays, calculate their sum and return the result as an array.

• Iterate through the arrays from right to left, adding digits and carrying over if necessary

• Handle cases where one array is longer than the other by considering the remaining digits

• Ensure the final sum array does not have any leading zeros

Reverse a given integer while excluding trailing zeros.

• Create a program to reverse the given integer by converting it to a string and then reversing it.

• Remove any trailing zeros from the reversed string before converting it back to an integer.

• Handle the constraints of the input integer being between 0 and 10^8.

• Example: For input 1230, the output should be 321.

To solve the Set Matrix Zeros problem, we can use O(1) space by utilizing the first row and column to store information about zeros in the rest of the matrix.

• Iterate through the matrix and use the first row and column to mark rows and columns that need to be zeroed out.

• After marking, iterate through the matrix again and zero out the rows and columns based on the marks in the first row and column.

• Remember to handle the special case of the first row and column separately.

• Exampl...read more

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 as the last node encountered during the reversal process.

Implement a function to return elements of a matrix in spiral order.

• Iterate through the matrix in a spiral order by adjusting boundaries as you move along.

• Keep track of the direction of movement (right, down, left, up) to traverse the matrix correctly.

• Handle edge cases like when the matrix is a single row or column separately.

Stored procedures are precompiled SQL statements that can be executed on demand, while triggers are automatically executed in response to specific events.

• Stored procedures are explicitly called by the user, while triggers are automatically invoked by the database system.

• Stored procedures can accept parameters and return values, while triggers cannot.

• Stored procedures can be executed independently, while triggers are always associated with a specific table or view.

• Stored proce...read more

Given an array of integers, remove K elements from either end to maximize sum of remaining elements.

• Iterate through all possible combinations of removing K elements from start and end

• Calculate sum of remaining elements for each combination

• Return the maximum sum obtained

C program to find P and Q (P>Q) such that A[P] - A[Q] is maximum

• Iterate through array and keep track of maximum difference and corresponding indices

• Initialize P and Q to first two elements and update as necessary

• Time complexity: O(n)

Find the maximum sum of any contiguous subarray within an array in O(N) time complexity.

• Use Kadane's algorithm to find the maximum sum subarray in O(N) time complexity

• Initialize max_sum and current_sum to the first element of the array

• Iterate through the array, updating current_sum and max_sum as needed

• Return max_sum as the maximum sum of any contiguous subarray

The seven layers of networking refer to the OSI model which defines how data is transmitted over a network.

• The seven layers are: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

• Each layer has a specific function and communicates with the layers above and below it.

• For example, the Physical layer deals with the physical transmission of data, while the Application layer deals with user interfaces and applications.

• Understanding the OSI model is imp...read more