ZL Technologies Interview Questions and Answers

To find a loop in a linked list, we use Floyd's cycle-finding algorithm.

• Floyd's cycle-finding algorithm uses two pointers, one moving at twice the speed of the other.

• If there is a loop in the linked list, the two pointers will eventually meet.

• To detect the meeting point, we reset one of the pointers to the head of the linked list and move both pointers at the same speed.

• The meeting point is the start of the loop.

LRU, MRU and LFU are caching algorithms used to manage memory in computer systems.

• LRU stands for Least Recently Used and removes the least recently used items from the cache when the cache is full.

• MRU stands for Most Recently Used and removes the most recently used items from the cache when the cache is full.

• LFU stands for Least Frequently Used and removes the least frequently used items from the cache when the cache i...read more

Windows and UNIX have several technical differences.

• Windows has a graphical user interface (GUI) while UNIX is primarily command-line based.

• Windows uses the NTFS file system while UNIX typically uses the ext4 file system.

• Windows supports a wide range of software applications, while UNIX is known for its stability and security.

• Windows has a larger user base and is more commonly used for personal computers, while UNIX is...read more

NTFS and FAT are file systems used in Windows operating systems with differences in features and capabilities.

• NTFS supports file and folder permissions, while FAT does not.

• NTFS has built-in support for file compression and encryption, while FAT does not.

• NTFS has a journaling feature that helps in recovering from system crashes, while FAT does not.

• NTFS supports larger file sizes and partition sizes compared to FAT.

• NTFS ...read more

The OSI stack consists of 7 layers that define the functions and protocols of network communication.

• Physical layer: Deals with the physical transmission of data.

• Data Link layer: Provides error-free transmission over a physical link.

• Network layer: Handles routing and logical addressing.

• Transport layer: Ensures reliable data delivery and manages end-to-end connections.

• Session layer: Establishes, manages, and terminates s...read more

NAT (Network Address Translation) is a technique used to translate private IP addresses to public IP addresses, allowing devices on a private network to communicate with the internet. DHCP (Dynamic Host Configuration Protocol) is a network protocol that automatically assigns IP addresses and other network configuration parameters to devices on a network.

• NAT allows multiple devices on a private network to share a single...read more

A hub is a simple networking device that connects multiple devices in a network. A switch is a more advanced device that filters and forwards data packets. A router is a device that connects multiple networks and directs data packets between them.

• A hub operates at the physical layer of the OSI model, while a switch operates at the data link layer.

• A hub broadcasts data to all connected devices, while a switch selectivel...read more

Collision domain is a network segment where collisions can occur. Bridges segregate collision domains by creating separate segments.

• Collision domain is a section of a network where network devices share the same bandwidth and can collide with each other.

• Collisions occur when two or more devices transmit data simultaneously on a shared medium.

• Bridges create separate collision domains by dividing a network into multiple ...read more

A combination of array and hashmap can be used to design the underlying data structures for an educational institution's website.

• Use an array to store the departments available in the institution.

• Each department can be represented as a key in the hashmap.

• The value corresponding to each department key in the hashmap can be another hashmap.

• This nested hashmap can store the courses available in the department.

• The courses ...read more

Design considerations for a client-server system with virtual operating systems on the fly

• Scalability: Ensure the system can handle multiple clients requesting virtual operating systems simultaneously

• Resource allocation: Manage resources efficiently to provide virtual operating systems to clients

• Network bandwidth: Optimize network usage to deliver virtual operating systems quickly

• Security: Implement measures to protect...read more

VMware's virtualization on a multicore machine allows for efficient utilization of resources and improved performance.

• VMware's virtualization technology enables the creation of multiple virtual machines (VMs) on a single multicore machine.

• Each VM can run its own operating system and applications, isolated from other VMs.

• The hypervisor, such as VMware ESXi, manages the allocation of CPU, memory, and other resources to e...read more

The minimum number of packets required to pack 51 apples such that any number of apples between 1 and 51 can be given.

• The minimum number of packets required is 6.

• Each packet should contain a power of 2 number of apples.

• The packets should be of sizes: 1, 2, 4, 8, 16, and 20.

• By combining these packets, any number of apples between 1 and 51 can be given.

Program to implement strstr function in C++

• Use two nested loops to compare each character of the haystack and needle

• If a match is found, return the starting index of the substring

• If no match is found, return -1

To construct an almost balanced binary tree from an incoming stream of numbers.

• Use a self-balancing binary search tree like AVL or Red-Black tree.

• Insert the numbers from the stream into the tree.

• Perform rotations or rebalancing operations as necessary to maintain balance.

• Consider using a priority queue to handle the incoming stream efficiently.

Implementing autocomplete feature for search queries

• Use a trie data structure to store the search queries

• As the user types, traverse the trie to find matching prefixes

• Return the suggestions based on the matching prefixes

• Consider using a ranking algorithm to prioritize suggestions

A semaphore is a synchronization object that controls access to a shared resource through the use of a counter.

• Semaphores can be used to limit the number of threads accessing a resource simultaneously.

• They can be used to solve the critical section problem in concurrent programming.

• Semaphores can have two types: counting semaphores and binary semaphores.

• Counting semaphores allow a specified number of threads to access a...read more

The P and V operations are used to control access to a shared resource using a semaphore.

• P operation (wait operation) decreases the value of the semaphore by 1, blocking if the value is already 0.

• V operation (signal operation) increases the value of the semaphore by 1, releasing a waiting process if any.

• P and V operations are typically used in synchronization mechanisms to prevent race conditions and ensure mutual excl...read more

REST web service is an architectural style for designing networked applications that use HTTP as the communication protocol.

• REST stands for Representational State Transfer

• It is based on a client-server model

• It uses standard HTTP methods like GET, POST, PUT, DELETE

• Resources are identified by URIs

• Responses are typically in JSON or XML format

HTTP is a stateless protocol.

• HTTP is stateless because it does not retain any information about previous requests or responses.

• Each request is treated as an independent transaction, and the server does not maintain any knowledge of the client's state.

• To maintain state, cookies or session management techniques can be used.

• Statelessness allows for scalability and simplicity in web applications.

Shared memory is a memory space that can be accessed by multiple processes or threads simultaneously.

• Shared memory allows processes or threads to communicate and share data efficiently.

• It is typically used in inter-process communication (IPC) to avoid the overhead of copying data between processes.

• Shared memory can be implemented using operating system mechanisms like memory-mapped files or system calls.

• Example: Multip...read more

Alignment issues in structures occur due to memory padding and alignment requirements.

• Structures may have unused memory space due to alignment requirements.

• Padding is added to align structure members on memory boundaries.

• Alignment issues can lead to wasted memory and decreased performance.

• Compiler directives like #pragma pack can be used to control alignment.

• Example: struct MyStruct { char a; int b; char c; };

Memory Management Unit (MMU) is a hardware component that manages memory access and translation between virtual and physical addresses.

• MMU is responsible for translating virtual addresses used by programs into physical addresses in the computer's memory.

• It provides memory protection by assigning access permissions to different memory regions.

• MMU also handles memory allocation and deallocation, ensuring efficient use of...read more

A socket is an endpoint for communication between two machines over a network.

• A socket is a software abstraction that allows programs to send and receive data over a network.

• It provides a mechanism for inter-process communication between applications running on different machines.

• Sockets can be used for various network protocols such as TCP/IP, UDP, etc.

• They are identified by an IP address and a port number.

• Examples of...read more

Yes, it is possible to declare a structure 'a' that contains a structure 'b' and 'b' in turn contains 'a'.

• To achieve this, we can use forward declaration of one of the structures.

• By using a pointer or reference to the other structure inside the first structure, we can avoid recursive definition.

• This allows us to create a nested structure hierarchy.

To find the offset of a member of a structure object, use the 'offsetof' macro. If not allowed to create the object, use 'sizeof' and pointer arithmetic.

• Use the 'offsetof' macro to find the offset of a member within a structure object

• If not allowed to create the object, use 'sizeof' to get the size of the structure and perform pointer arithmetic

Netapp is a multinational storage and data management company.

• Netapp specializes in providing storage solutions for businesses and organizations.

• They offer a wide range of products and services including storage systems, software, and cloud services.

• Netapp's solutions help organizations manage and protect their data, improve efficiency, and enable data-driven decision making.

• They have a strong presence in the enterpris...read more

I come from a close-knit family with two siblings, an older brother and a younger sister.

• Close-knit family

• Two siblings - older brother and younger sister

I am interested in job profiles that involve software development, problem-solving, and continuous learning.

• I prefer job profiles that allow me to work on challenging projects and utilize my technical skills.

• I am interested in roles that involve software development, coding, and debugging.

• I enjoy problem-solving and would like a job that challenges me to think creatively and analytically.

• I value continuous learning and

IP tables is a firewall configuration tool in Linux.

• IP tables is used to filter network traffic based on a set of rules.

• It can be used to block or allow traffic based on source/destination IP address, port number, protocol, etc.

• IP tables is configured using the command line interface.

• It is commonly used in Linux servers to secure the network.

• Example: iptables -A INPUT -s 192.168.1.0/24 -j DROP

Program to traverse a linked list

• Start from the head node

• Iterate through each node until the end is reached

• Perform necessary operations on each node

Program to reverse a linked list using extra space.

• Create a new empty linked list

• Traverse the original linked list and push each node to the new linked list

• Return the new linked list as the reversed linked list

Find the total number of matches to be played in a knockout football tournament with n teams.

• The number of matches played in a knockout tournament is always one less than the number of teams.

• Use the formula (n-1) to calculate the total number of matches.

• For example, in a tournament with 8 teams, the total number of matches played would be 7.

Find closest ancestor of two nodes in a tree

• Traverse the tree from root to both nodes and store the paths

• Compare the paths to find the closest common ancestor

• Use recursion to traverse the tree and find the ancestor

• If one node is an ancestor of the other, return the ancestor node

Segmentation fault is a type of error that occurs when a program tries to access a memory location that it is not allowed to access.

• Segmentation fault is also known as segfault.

• It is a common error in C and C++ programming languages.

• It occurs when a program tries to access a memory location that it is not allowed to access, such as an area of memory that has not been allocated to the program.

• This can happen due to a va...read more

To find the maximum number from a million numbers entered on the fly or 1000 at a time.

• Create a variable to store the maximum number and initialize it to the first number entered

• Compare each subsequent number entered with the current maximum and update the variable if necessary

• If numbers are given 1000 at a time, store the maximum of each batch and compare them at the end to find the overall maximum

Variables for kernel level process should be stored in stack.

• Stack is faster than heap for accessing variables.

• Stack is limited in size, so use it for small variables.

• Heap is used for larger variables that need to persist beyond the function call.

• Kernel level processes should avoid dynamic memory allocation.

Internal fragmentation is the unused memory space within a partition or block.

• Occurs when allocated memory is larger than required

• Leads to inefficient use of memory

• Can be reduced by using memory allocation techniques like paging or segmentation

In C, structure variables cannot be directly compared using the comparison operators. Cell padding is used to align data in memory for efficiency.

• Structure variables in C cannot be compared directly using comparison operators like == or !=. Instead, you need to compare each member of the structure individually.

• Cell padding refers to the practice of adding empty bytes between structure members to align them in memory. T...read more

Global variables are stored in data segment while local variables are stored in stack memory.

• Global variables are accessible throughout the program while local variables are only accessible within their scope.

• Global variables are initialized to default values while local variables are not.

• Global variables can be modified by any function while local variables can only be modified within their scope.

Control is passed through function calls. Return address of main is stored in the stack.

• Control is passed to a function when it is called from main()

• The function executes and returns control to main() using the return statement

• The return address of main() is stored in the stack

• When the function returns, the return address is used to resume execution in main()

To calculate square root without math.h, use Newton's method.

• Choose a number to find the square root of

• Make an initial guess for the square root

• Use Newton's method to refine the guess

• Repeat until desired accuracy is achieved

• Newton's method: new_guess = (guess + (number/guess))/2

Find the lowest floor from which an egg breaks when dropped from a 30 floor building with 4 eggs.

• Use binary search approach to minimize the number of drops

• Start dropping the egg from the middle floor and check if it breaks

• If it breaks, start dropping from the middle of the lower half, else start from the middle of the upper half

• Repeat the process until the lowest floor is found

Using a heap in Q6 can have certain disadvantages.

• Heap operations are slower than array operations.

• Heap requires extra memory allocation.

• Heap may not be suitable for small datasets.

• Heap may not be efficient for certain types of data structures.

• Heap may lead to fragmentation of memory.

I interned at XYZ company and developed a software using Agile methodology. Faced challenges in meeting deadlines.

• Interned at XYZ company and developed a software

• Used Agile methodology for software development

• Faced challenges in meeting deadlines

• Collaborated with team members to overcome challenges

Engineering solution to reduce plastic waste

• Develop biodegradable plastics

• Create recycling machines for households

• Implement a deposit system for plastic bottles

• Encourage the use of reusable bags and containers

• Design products with minimal packaging

• Develop a system to convert plastic waste into fuel

I really enjoyed the section on your development process.

• The detailed explanation of your agile methodology was impressive.

• The emphasis on collaboration and communication stood out to me.

• The use of real-life examples to illustrate your process was helpful.

• I appreciated the focus on continuous improvement and learning.

• Overall, it gave me a good understanding of how your team works and what to expect if I were to join.

Yes, my role as a software developer at NetApp is clear.

• My role is to develop and maintain software applications for NetApp.

• I work closely with other developers, project managers, and stakeholders to ensure that the software meets the needs of the business.

• I am responsible for writing clean, efficient, and well-documented code.

• I also participate in code reviews and contribute to the overall development process.

• For exam...read more

I enjoyed computer science and mathematics the most in college.

• Computer Science - I loved learning about algorithms, data structures, and programming languages.

• Mathematics - I enjoyed solving complex problems and understanding mathematical concepts.

Participated in various technical and cultural events, volunteered for social causes.

• Participated in coding competitions like CodeChef, HackerRank, etc.

• Organized technical events like hackathons, coding workshops, etc.

• Volunteered for social causes like blood donation camps, cleanliness drives, etc.

• Participated in cultural events like dance competitions, music concerts, etc.