SDE - 1

Approach : 

1) Initialize an array ‘ANS’ of integer type and the same size as the input array to store the Next Greater Elements.

2) Declare a stack ‘S’ of integer type that will have Next Greater Element as its top element.

3) Iterate the array in reverse order. (say, iterator = ‘i’)

4) Pop from ‘S’ until the stack ‘S’ is not empty and the current element is greater than the top element of the stack

5) Update ‘ANS[i]’ with the top element of ‘S’.

6) If the stack is empty then update ‘ANS[i]’ with -1.

7) Push the current element onto the stack ‘S’.

8) Return ‘ANS’.


TC : O(N), where N=number of elements in the array
SC : O(N)

Approach : 

1) Sort the array in descending order.
2) Print all the ones, if present.
3) From the remaining array print it in descending order making sure not to reprint the ones again.


TC : O(N * log(N)), where N=size of the array.
SC : O(1)

Approach : 

Finding the cycle : 

1) Initialize slow and fast at the beginning.
2) Start moving slow to every next node and move fast 2 jumps, while making sure that fast and its next is not null.
3) If slow and fast refer to the same node anytime during the process, there is a cycle, otherwise, repeat the process.
4) If fast reaches the end or NULL, then the execution stops and we can conclude that no cycle exists.

Removing the cycle : 

1) Find the length of the cycle, let’s say ‘L’.
2) We will take two pointers ‘ptr1’ and ‘ptr2’, initially ‘ptr1’ points to head and ‘ptr2’ points to Lth node from the head.
3) We will move the pointers until they meet at the same node.
4) To remove the cycle we have to find the previous node of the ‘ptr2’ and change its ‘next’ values to NULL.


TC : O(N), where N=number of nodes in the Linked List
SC : O(1)

Approach : 

1) Traverse the matrix element by element and compare ‘MATRIX' ( i, j) with 'MATRIX" ( j, i).

2) And if anywhere there inequality exists between them simply return false from that point else continue.

3) In the end, if not returned previously from anywhere else just return true, as ‘MATRIX’ is symmetric.

TC : O(N^2), where N=size of the square matrix
SC : O(1)

NORMALIZATION :
1) Normalization is a process of reducing redundancy by organizing the data into multiple tables.
2) Normalization leads to better usage of disk spaces and makes it easier to maintain the integrity of the database.


DENORMALIZATION :
1) Denormalization is the reverse process of normalization as it combines the tables which have been normalized into a single table so that data retrieval becomes faster.
2) JOIN operation allows us to create a denormalized form of the data by reversing the normalization.

Open System Interconnections (OSI) is a network architecture model based on the ISO standards. It is called the OSI model as it deals with connecting the systems that are open for communication with other systems.

The OSI model has seven layers. The principles used to arrive at the seven layers can be summarized briefly as below :

1) Create a new layer if a different abstraction is needed.
2) Each layer should have a well-defined function.
3) The function of each layer is chosen based on internationally standardized protocols.

Unicast : The unicast addressing method indicates that communication through a network involves a unique sender (source) and a single receiver (destination). Making an analogy, we can see unicast communication as a particular conversation with a single person (unicast) at a party with many people (network).


Multicast : A multicast address can be used to deliver a package to a group of destinations. Any packet sent to a multicast address, will be delivered to every host that has joined that particular group.Since IPv6 has no support for the broadcast address, any function that used to rely on broadcasts will now be using multicast addresses.Multicast addresses are in the range of FF00::/8.


Anycast : The anycast address is very similar to the multicast address, but packets will be delivered to only one random host, instead of the entire group.Anycast address don’t have a specific range, as they are exactly the same as regular unicast addresses. This means that a hosts has no way to distinguish a unicast from an anycast address when it sends a packet.

It is generally a situation where the CPU performs less productive work and more swapping or paging work. It spends more time swapping or paging activities rather than its execution. By evaluating the level of CPU utilization, a system can detect thrashing. It occurs when the process does not have enough pages due to which the page-fault rate is increased. It inhibits much application-level processing that causes computer performance to degrade or collapse.

Deadlock is generally a situation where a set of processes are blocked as each process is holding resources and waits to acquire resources held by another process. In this situation, two or more processes simply try to execute simultaneously and wait for each to finish their execution because they are dependent on each other. We can see a hand problem in our system whenever a deadlock occurs in a program. It is one of the common problems you can see in multiprocessing. 

Necessary Conditions for Deadlock

There are basically four necessary conditions for deadlock as given below:

1) Mutual Exclusion
2) Hold and Wait
3) No Pre-emption
4) Circular Wait or Resource Wait

If you get this question, it's an opportunity to choose the most compelling information to share that is not obvious from your resume.

Example :

Strength -> I believe that my greatest strength is the ability to solve problems quickly and efficiently, which makes me unique from others.

Abillity to Handle Pressure -> I enjoy working under pressure because I believe it helps me grow and become more efficient .

Tip : Emphasize why you were inspired to apply for the job. You can also explain that you are willing to invest a great deal of energy if hired.

These are generally very open ended questions and are asked to test how quick wit a candidate is. So there is nothing to worry about if you have a good command over your communication skills and you are able to propagate your thoughts well to the interviewer