SDE - 1

Steps :
1. If the head node is the key to be deleted ,make the head node point to the next node and free its memory.
2. Otherwise, traverse the linked list from the current node and check whether the next node has the given key. If yes, make the current->next = current->next->next and free the memory.
Time Complexity : O(N) where n is the length of the linked list

TOP keyword can be used to find the nth highest salary. By default ORDER BY clause print rows in ascending order, since we need the highest salary at the top, we have used ORDER BY DESC, which will display salaries in descending order. Again DISTINCT is used to remove duplicates. The outer query will then pick the topmost salary, which would be your Nth highest salary.
SQL query : 
SELECT TOP 1 salary
FROM ( 
SELECT DISTINCT TOP N salary
FROM #Employee 
ORDER BY salary DESC 
) AS temp
ORDER BY salary

The building blocks of OOPs are : 
1. Classes & Objects : An Object can be defined as an entity that has a state and behavior. Class is basically a collection of objects which act as building blocks. 
2. Abstraction : It helps in displaying the essential features without showing the details or the functionality to the user. It avoids unnecessary information or irrelevant details and shows only that specific part which the user wants to see.
3. Encapsulation: The wrapping up of data and functions together in a single unit is known as encapsulation. It can be achieved by making the data members' scope private and the member function’s scope public to access these data members.
4. Inheritance: Inheritance is the process in which two classes have an is-a relationship among each other and objects of one class acquire properties and features of the other class. The class which inherits the features is known as the child class, and the class whose features it inherited is called the parent class.
5. Polymorphism: Polymorphism is defined as the ability to take more than one form. It is a feature that provides a function or an operator with more than one definition. It can be implemented using function overloading, operator overload, function overriding, virtual function.

Concept of heaps can be used to find the kth maximum element. A max heap can be used. We add all the elements to a heap, with the largest at the top, and then pop the heap for k - 1 times, then the one on the top is our target. In STL, both priority_queue and multiset can be used as a min/max-heap.
Time Complexity : O(NlogK)

A C++ virtual function is a member function in the base class that you redefine in a derived class. It is declared using the virtual keyword. It is used to tell the compiler to perform dynamic linkage or late binding on the function. A 'virtual' is a keyword preceding the normal declaration of a function. When the function is made virtual, C++ determines which function is to be invoked at the runtime based on the type of the object pointed by the base class pointer.

Tip 1: Firstly, remember that the system design round is extremely open-ended and there’s no such thing as a standard answer. Even for the same question, you’ll have a totally different discussion with different interviewers.
Tip 2:Before you jump into the solution always clarify all the assumptions you’re making at the beginning of the interview. Ask questions to identify the scope of the system. This will clear the initial doubt, and you will get to know what are the specific detail interviewer wants to consider in this service.
Tip 3 : Design your structure and functions according to the requirements and try to convey your thoughts properly to the interviewer so that you do not mess up while implementing the idea .

Tip 1 : The cross questioning can go intense some time, think before you speak.
Tip 2 : Be open minded and answer whatever you are thinking, in these rounds I feel it is important to have opinion.
Tip 3 : Context of questions can be switched, pay attention to the details. It is okay to ask questions in these round, like what are the projects currently the company is investing, which team you are mentoring. How all is the work environment etc.
Tip 4 : Since everybody in the interview panel is from tech background, here too you can expect some technical questions. No coding in most of the cases but some discussions over the design can surely happen.