300+ Interview Questions and Answers

The task is to find the maximum amount you can definitely win in a game of coins against an opponent who plays optimally.

• The game is played with alternating turns, and each player can pick the first or last coin from the line.

• The value associated with the picked coin adds up to the total amount the player wins.

• To maximize your winnings, you need to consider all possible combinations of coin picks.

• Use dynamic programming to calculate the maximum amount you can win.

• Keep track o...read more

This question asks for finding the maximum number of vaccines administered on a specific day during a vaccination drive, given the total number of days, total number of vaccines available, and the day number.

• Read the number of test cases

• For each test case, read the number of days, day number, and total number of vaccines available

• Implement a logic to find the maximum number of vaccines administered on the given day number

• Print the maximum number of vaccines administered for e...read more

This is a problem where we need to search for a given number in a rotated sorted array.

• The array is sorted and then rotated, so we can use binary search to find the number.

• We can find the pivot point where the rotation happened and then perform binary search on the appropriate half of the array.

• To find the pivot point, we can use a modified binary search algorithm.

• Once we find the pivot point, we can determine which half of the array the target number lies in and perform bina...read more

The task is to find the smallest number greater than the given number, with the same set of digits.

• Iterate through the digits of the given number from right to left.

• Find the first digit that is smaller than the digit to its right.

• Swap this digit with the smallest digit to its right that is greater than it.

• Sort the digits to the right of the swapped digit in ascending order.

• If no such digit is found, return -1.

A /24 address can have 256 clients. Network address is the first IP and broadcast address is the last IP.

• A /24 address has 256 IP addresses

• The network address is the first IP in the range

• The broadcast address is the last IP in the range

A router is needed to connect two computers in different networks or to share internet connection.

• When two computers are in different networks, a router is needed to connect them.

• A router can also be used to share internet connection between multiple devices.

• Routers can provide additional security features like firewall and VPN.

• Examples of routers include Cisco, Netgear, and TP-Link.

ArrayList is a resizable array while LinkedList is a doubly linked list.

• ArrayList is faster for accessing elements while LinkedList is faster for adding or removing elements.

• ArrayList uses contiguous memory while LinkedList uses non-contiguous memory.

• ArrayList is better for random access while LinkedList is better for sequential access.

• Example: ArrayList - List names = new ArrayList<>(); LinkedList - List names = new LinkedList<>();

Possible security issues and how to manage them in web applications

• SQL injection attacks

• Cross-site scripting (XSS) attacks

• Cross-site request forgery (CSRF) attacks

• Insecure authentication and authorization mechanisms

• Sensitive data exposure

• Implementing secure coding practices

• Regularly updating software and security patches

• Conducting regular security audits and penetration testing

• Implementing multi-factor authentication

• Using HTTPS and SSL/TLS encryption

• Limiting access to sensiti...read more

Object-oriented languages support inheritance and polymorphism, while object-based languages do not.

• Object-oriented languages allow for the creation of classes and objects, and support inheritance and polymorphism.

• Object-based languages only support objects, but do not have the concept of classes or inheritance.

• Examples of object-oriented languages include Java, C++, and Python, while JavaScript is an example of an object-based language.

An algorithm to schedule matches in a tournament with N teams, where each team plays only one match per day.

• Create a round-robin schedule where each team plays every other team once.

• Start by assigning each team a number.

• Generate a schedule by pairing teams based on their numbers.

• Optimize the schedule by minimizing the number of days required.

• Consider using a graph-based approach to find the optimal schedule.

Entering a URL in the browser triggers a series of events to retrieve and display the requested webpage.

• The browser checks the cache for a previously stored copy of the webpage

• If not found, the browser sends a request to the DNS server to resolve the domain name to an IP address

• The browser then sends a request to the web server at the IP address for the webpage

• The web server responds with the requested webpage

• The browser renders the webpage and displays it to the user

Virtual memory is a memory management technique that allows a computer to use more memory than physically available.

• Virtual memory is created by using hard disk space as an extension of RAM.

• It allows running more programs than the physical memory can handle.

• The size of virtual memory is typically larger than the size of main memory.

• Virtual memory is divided into pages, which are swapped in and out of main memory as needed.

• Examples of virtual memory include Windows pagefile an...read more

Anycast, unicast, and multicast are different ways of routing network traffic.

• Unicast is one-to-one communication between a sender and a receiver.

• Anycast is one-to-nearest communication where the sender sends a message to the nearest receiver.

• Multicast is one-to-many communication where the sender sends a message to a group of receivers.

• Anycast is used for load balancing and finding the nearest server.

• Unicast is used for regular client-server communication.

• Multicast is used f...read more

RSTP BPDU introduces two new flags: TCN and Proposal.

• TCN (Topology Change Notification) flag is used to indicate a topology change in the network.

• Proposal flag is used to speed up the convergence process by allowing a switch to immediately transition to the forwarding state.

• TCN flag is set by the root bridge and propagated to all switches in the network.

• Proposal flag is set by a switch and sent to the root bridge.

• Both flags are included in the BPDU message.

• TCN flag triggers a...read more

Async in JS allows non-blocking code execution despite being single-threaded.

• JS uses event loop to handle async operations

• Callbacks, Promises, and Async/Await are used for async programming

• setTimeout() and setInterval() are examples of async functions

• JS runtime delegates async tasks to the browser or Node.js environment

• Async code can improve performance and user experience

To link up two routers with OSPF enabled but link down, specific methods include checking physical connections, verifying OSPF configurations, and troubleshooting network issues.

• Check physical connections and ensure cables are properly connected and not damaged

• Verify OSPF configurations and ensure that the routers are configured with the same OSPF process ID and network type

• Troubleshoot network issues by checking for any network outages or misconfigurations

• Use tools such as p...read more

MAC addresses are required for identifying devices on a local network, while IP addresses are used for identifying devices on a global network.

• MAC addresses are used for communication within a local network

• IP addresses are used for communication across different networks

• MAC addresses are assigned by the manufacturer and cannot be changed

• IP addresses can be assigned dynamically or statically

• MAC addresses are used in the data link layer of the OSI model

• IP addresses are used in ...read more

The method returns the least common multiple (LCM) of two numbers m and n.

• The method uses prime factorization to find the LCM.

• It iterates through all prime numbers less than m and n.

• For each prime number, it finds the largest power of the prime that divides both m and n.

• The method then multiplies the current LCM by the prime raised to the maximum power.

• Finally, it returns the computed LCM.

Program to print binary tree elements in spiral order

• Use two stacks to keep track of nodes at odd and even levels

• Push nodes from left to right in odd level stack and right to left in even level stack

• Pop nodes from the stack alternatively and print them

• Repeat until both stacks are empty

Programs to find second largest in an integer array and denomination to get amount.

• For finding the second largest number, sort the array in descending order and return the second element.

• For finding the denomination, loop through the array of denominations and keep dividing the amount until it becomes zero.

• Use integer division to get the number of notes of each denomination.

To troubleshoot SSH issue, check network connectivity, firewall settings, SSH configuration, and user permissions.

• Check if the server is reachable over the network

• Verify if the SSH service is running on the server

• Check if the firewall is blocking SSH traffic

• Verify SSH configuration on the server

• Check if the user has the necessary permissions to access the server

• Check SSH logs for any errors or warnings

DHCP is a network protocol that automatically assigns IP addresses to devices on a network.

• DHCP stands for Dynamic Host Configuration Protocol.

• It allows devices to obtain IP addresses, subnet masks, default gateways, and other network configuration settings automatically.

• DHCP uses a client-server model, where the DHCP server assigns IP addresses to clients.

• The DHCP server maintains a pool of available IP addresses and leases them to clients for a specific period of time.

• When ...read more

Algorithm to find elements appearing more than n/3 times in an array in linear time

• Divide the array into three equal parts

• Iterate through the array and count the occurrences of each element in each part

• Check if the count of any element is greater than n/3

• Return the elements that meet the condition

No, it is not possible to use a variable defined as both static and global in base file using extern.

• A variable cannot be both static and global at the same time.

• Static variables have file scope and cannot be accessed from other files using extern.

• Global variables can be accessed from other files using extern, but cannot be static.

• Therefore, it is not possible to use a variable defined as both static and global in base file using extern.

IPv4 has 32 bits and IPv6 has 128 bits.

• IPv4 addresses are in the format of xxx.xxx.xxx.xxx where each xxx is an 8-bit number.

• IPv6 addresses are in the format of xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx where each xxxx is a 16-bit number.

• IPv6 addresses allow for a much larger number of unique addresses than IPv4.

The correct address of a[4][3] in the given array is 1056.

• The base address of the array is 1000.

• Each element in the array occupies a certain amount of memory.

• To calculate the address of a specific element, we need to consider the size of each element and the dimensions of the array.

Inheritance is a way to create new classes based on existing ones. Abstraction is a way to hide implementation details.

• Inheritance allows a subclass to inherit properties and methods from a superclass.

• Abstraction allows a class to provide a simplified interface to its users while hiding its implementation details.

• For example, a Car class can inherit properties and methods from a Vehicle class, while also implementing its own unique features.

• Abstraction can be seen in a TV rem...read more

When you type google.com on your web browser, it sends a request to Google's server and loads the website.

• The browser sends a DNS request to resolve the domain name 'google.com' to an IP address

• The browser establishes a TCP connection with Google's server

• The browser sends an HTTP request to the server for the homepage of google.com

• The server responds with the HTML code for the homepage

• The browser renders the HTML code and displays the webpage

Use the sizeof operator on a variable of type int to get its size.

• Use sizeof operator on a variable of type int

• Size of int is typically 4 bytes

• Size may vary depending on the system architecture

Size of union in C is allocated based on the size of the largest member.

• The size of the union is equal to the size of the largest member.

• The memory allocated for a union is shared by all its members.

• Unions are used to save memory when only one member is accessed at a time.

Event bubble and capture are two ways of propagating events in the DOM tree.

• Event bubble is the default behavior where an event is first captured by the innermost element and then propagated to the outer elements.

• Event capture is the opposite of event bubble where an event is first captured by the outermost element and then propagated to the inner elements.

• Both event bubble and capture can be used together to handle events in a more controlled way.

• Event.stopPropagation() meth...read more

Boundary problem refers to the difficulty in deciding the optimal size of structures to allocate resources.

• It involves determining the trade-off between the benefits of larger structures and the costs of building and maintaining them.

• The problem is particularly relevant in fields such as architecture, civil engineering, and urban planning.

• For example, in urban planning, deciding the optimal size of roads, buildings, and parks can have a significant impact on the quality of li...read more

TCP is a protocol that ensures reliable communication by establishing a connection, managing data transfer, and handling errors.

• TCP establishes a connection between two devices before data transfer begins.

• It breaks data into packets and numbers them for sequencing.

• It uses acknowledgments and retransmissions to ensure all packets are received.

• TCP handles flow control by adjusting the transmission rate based on receiver's capacity.

• It also handles congestion control by detecting...read more

Implement a queue using two stacks by using one stack for enqueue operation and another stack for dequeue operation.

• Use one stack for enqueue operation by pushing elements onto it.

• Use another stack for dequeue operation by popping elements from it. If the dequeue stack is empty, transfer all elements from the enqueue stack to the dequeue stack.

• Maintain the order of elements by transferring elements between the two stacks as needed.

Motivating a customer on escalation edge

• Show empathy and understanding of their frustration

• Provide regular updates on the progress of the case

• Offer solutions or workarounds to mitigate the issue

• Highlight the importance of resolving the issue for their business

• Escalate the case to higher management if necessary

• Thank them for their patience and cooperation