NetApp Interview Questions, Process, and Tips

Round duration - 60 minutes
Round difficulty - Easy

This was the first technical round.

Q1. 
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. 
This can be solved both: recursively and iteratively.
The recursive approach is more intuitive. First reverse all the nodes after head. Then we need to set head to be the final node in the reversed list. We simply set its next node in the original list (head -> next) to point to it and sets its next to NULL. The recursive approach has a O(N) time complexity and auxiliary space complexity.
For solving the question is c...read more
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Q2. 
LCA of Binary Tree Problem Statement
You are given a binary tree consisting of distinct integers and two nodes, X and Y. Your task is to find and return the Lowest Common Ancestor (LCA) of these two nodes...read more
Ans. 
The recursive approach is to traverse the tree in a depth-first manner. The moment you encounter either of the nodes node1 or node2, return the node. The least common ancestor would then be the node for which both the subtree recursions return a non-NULL node. It can also be the node which itself is one of node1 or node2 and for which one of the subtree recursions returns that particular node.

Pseudo code :
 
LowestC...read more
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Q3. What is internal fragmentation?
Ans. 
Internal fragmentation happens when the memory is split into mounted-sized blocks. Whenever a method is requested for the memory, the mounted-sized block is allotted to the method. just in case the memory allotted to the method is somewhat larger than the memory requested, then the distinction between allotted and requested memory is that the internal fragmentation.
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Q4. Which part of memory stores uninitialized static and global variables?
Ans. 
The uninitialized data segment is also known as a . bss segment that stores all the uninitialized global, local and external variables. If the global, static and external variables are not initialized, they are assigned with zero value by default.
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Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round with questions on DSA, OS, OOPS etc.

Q1. 
Integer Square Root Calculation
Given a positive integer 'N', compute its square root and return it. If 'N' is not a perfect square, then return the floor value of sqrt(N).
Example:
Input:
N = 25
N = 20
N...read more
Ans. 
The Simple Approach is to find the floor of the square root, try with all-natural numbers starting from 1. Continue incrementing the number until the square of that number is greater than the given number.
Algorithm: 
1. Create a variable (counter) i and take care of some base cases, i.e when the given number is 0 or 1.
2. Run a loop until i*i <= n , where n is the given number. Increment i by 1.
3. The floor of th...read more
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Q2. Where does the returned value for the 'main' function go?
Ans. 
In UNIX systems it looks something like this:

When you compile a program with gcc, it wraps a startup routine around your main() function. This routine calls your main() function and saves its return value. It then calls the exit() function (which your program might call as well), that does some general clean up. This function then again calls _exit(), which is a system call that tells the OS to save the returned value ...read more
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Q3. What is a segmentation fault?
Ans. 
Segmentation fault is a specific kind of error caused by accessing memory that “does not belong to you.” 
When a piece of code tries to do read and write operation in a read only location in memory or freed block of memory, it is known as core dump. It is an error indicating memory corruption.
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Round duration - 30 minutes
Round difficulty - Easy

This was a typical managerial round.

Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round with questions on DSA, Programming and OOPS.

Q1. 
Implement strstr() Function in C Problem Statement
Given two strings A and B, find the index of the first occurrence of A in B. If A is not present in B, return -1.
Example:
Input:
A = "bc", B = "abcdd...read more
Ans. 
Iterative implementation of strstr(): It returns a pointer to the first occurrence of Y in X or a null pointer if Y is not part of X. The time complexity of this solution is O(m.n) where m and n are the length of String X and Y, respectively.
 
// returns true if `X` and `Y` are the same
int compare(const char *X, const char *Y)
{
	while (*X && *Y)
	{
		if (*X != *Y) {
			return 0;
		}
		X++;
		Y++;
...read more
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Q2. What happens when we try to access a null pointer in C?
Ans. 
The standard says that accessing a NULL ptr is “undefined behavior”. Undefined behavior can be anything, including:
Nothing at all - continue running the program as if nothing happened
Crashing the application
Corrupting application data
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Q3. What are the phases of a compiler?
Ans. 
Phase 1: Lexical Analysis
Lexical Analysis is the first phase when compiler scans the source code. This process can be left to right, character by character, and group these characters into tokens.
Here, the character stream from the source program is grouped in meaningful sequences by identifying the tokens. It makes the entry of the corresponding tickets into the symbol table and passes that token to next phase.

Phase 2...read more
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Q4. What is a system stack?
Ans. 
The system stack (a.k.a. call stack or just "the stack") is a place in memory for things that the heap doesn't cover. The system stack is more organized than the heap since it uses the stack data structure, where order matters. Also, the address of the next allocation is known at all times because of this organization. Allocated items are pushed on to the stack in a particular order and popped off when needed. Most imp...read more
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Q5. 
Count Set Bits Problem Statement
Given an integer N, for each integer from 0 through N, find and print the number of set bits (1s) present in its binary representation.
Example:
Input:
N = 5
Output:
...read more
Ans. 
The direct approach would be to loop through all bits in an integer, check if a bit is set and if it is, then increment the set bit count.
Time Complexity: Θ(logn) (Theta of logn)
Auxiliary Space: O(1)
Brian Kernighan’s Algorithm can also be used here. 
This algorithm is based on the idea that subtracting 1 from a decimal number flips all the bits after the rightmost set bit(which is 1) including the rightmost set bit...read more
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Round duration - 60 minutes
Round difficulty - Easy

Technical Interview round with questions on DSA, Programming and OOPS.

Q1. 
Inorder Traversal of a Binary Tree Without Recursion
You are provided with a binary tree consisting of 'N' nodes, where each node contains an integer value. Your task is to perform the In-Order traversal ...read more
Ans. 
Inorder traversal requires that we print the leftmost node first and the right most node at the end. 
So basically for each node we need to go as far as down and left as possible and then we need to come back and go right. So the steps would be : 
1. Start with the root node. 
2. Push the node in the stack and visit it's left child.
3. Repeat step 2 while node is not NULL, if it's NULL then pop the topmost n...read more
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Q2. 
Detect Loop in Singly Linked List
Determine if a given singly linked list of integers contains a cycle.
Explanation:
A cycle in a linked list occurs when a node's next points back to a previous node in ...read more
Ans. 
Floyd's algorithm can be used to solve this question.
Define two pointers slow and fast. Both point to the head node, fast is twice as fast as slow. There will be no cycle if it reaches the end. Otherwise, it will eventually catch up to the slow pointer somewhere in the cycle.
Let X be the distance from the first node to the node where the cycle begins, and let X+Y be the distance the slow pointer travels. To catch up, t...read more
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Q3. What is an interrupt?
Ans. 
An interrupt is a special type of condition that occurs during the working of a microprocessor.
Microprocessor services the interrupt by executing a subroutine called interrupt service routine (ISR).
The interrupt can be given to the processor by the external signal(i.e. on external pins of a Microprocessor) or as a software interrupt or by the condition produced by the program.
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Q4. What is the CSMA protocol?
Ans. 
Carrier Sense Multiple Access (CSMA) is a network protocol for carriertransmission that operates in the Medium Access Control (MAC) layer. It senses or listens whether the shared channel for transmission is busy or not, and transmits if the channel is not busy. Using CMSA protocols, more than one users or nodes send and receive data through a shared medium that may be a single cable or optical fiber connecting multiple...read more
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Round duration - 30 minutes
Round difficulty - Easy

Typical Managerial round.