SDE - 1

The problem can be solved using the concept of sliding window. 
We scan the array from 0 to n-1, and maintain a deque to keep "promising" elements. 
At each i, we keep "promising" elements, which are potentially max number in window [i-(k-1),i] or any subsequent window. This means: 
1. If an element in the deque and it is out of i-(k-1), we discard them. We just need to remove from the head, as we are using a deque and elements are ordered as the sequence in the array
2. Now only those elements within [i-(k-1),i] are in the deque. We then discard elements smaller than a[i] from the tail. This is because if a[x] 3.As a result, elements in the deque are ordered in both sequence in array and their value. At each step the head of the deque is the max element in [i-(k-1),i]
The algorithm is amortized O(n) as each element is pushed and removed once.

ACID is a set of properties of database transactions intended to guarantee validity even in the event of errors, power failures, etc.
ACID stands for : 
1. Atomicity : All statements of a transaction must succeed completely, or fail completely in each and every situation, including power failures, errors and crashes. Example - Debiting and crediting in a money transfer transaction, both must happen either together or not at all.
2. Consistency : The database must remain in a consistent state after any transaction. Data in the database should not have any changes other than intended after the transaction completion.
3. Isolation : Isolation ensures that concurrent execution of transactions leaves the database in the same state that would have been obtained if the transactions were executed sequentially.
4. Durability :Durability guarantees that once a transaction has been committed, it will remain committed even in the case of a system failure which actually means recording the completed transactions (or their effects) in non-volatile memory.

Write-Ahead Logging (WAL) simply means that SQL Server needs to write the log records associated with a particular modification before it writes the page to the disk. This process ensures that no modifications to a database page will be flushed to disk until the associated transaction log records with that modification are written to disk firs to maintain the ACID properties of a transaction.

To avoid deadlocks, prior knowledge about the usage of resources by processes including resources available, resources allocated, future requests and future releases by processes can be used. Most deadlock avoidance algorithms need every process to tell in advance the maximum number of resources of each type that it may need. Based on all this info we may decide if a process should wait for a resource or not, and thus avoid chances for a circular wait. Deadlock avoidance can mainly be done with the help of Banker's Algorithm.
The bankers algorithm is used to avoid deadlock and allocate resources safely to each process in the computer system. The 'S-State' examines all possible tests or activities before deciding whether allocation should be allowed to each process. It also helps the operating system to successfully share resources between all the processes. The banker's algorithm is named because it checks whether a person should be sanctioned a loan amount or not to help the bank system safely simulate allocation resources.

A clustered index defines the order in which data is stored in the table which can be sorted in only one way. It is a type of index which sorts the data rows in the table on their key values. So, there can be an only a single clustered index for every table. In an RDBMS, usually, the primary key allows you to create a clustered index based on that specific column.

Tip 1 : Check each function separately for its correct functioning. 
Tip 2 : After identifying the wrong function, add debugging statements to identify which part of the function is wrong.

Virtual functions are member functions in the base class that have been redefined in derived classes. The virtual keyword is used to declare them. It instructs the compiler to perform dynamic linking or late binding on the function. In function declarations, a 'virtual' keyword precedes the normal declaration. C++ determines which virtual function is to be invoked based on the class of the object pointed by the class pointer when the function is made virtual.

malloc() : It stands for memory allocation. The malloc() function reserves a block of memory of the specified number of bytes. And, it returns a pointer of void which can be casted into pointers of any form.
free() : Dynamically allocated memory created with either calloc() or malloc() doesn't get freed on their own. You must explicitly use free() to release the space.

While memory allocation, one or more empty bytes are inserted (or left empty) between memory addresses which are allocated for other structure members. This is known as structure padding. A computer processor is designed in such a way that it can read one word from memory at a time. Because of this processor advantage, data is always aligned as a 4 byte package, which results in inserting empty addresses between other members' addresses. Because of this padding concept in C, the size of the structure is never as we think.

Tip 1 : Explain fault tolerant systems, 
Tip 2 : Describe the components of fault tolerant systems.

Tip 1 : Be sure to do your homework on the organization and its culture before the interview.
Tip 2 : Employers want to understand how you use your time and energy to stay productive and efficient. Be sure to emphasize that you adhere to deadlines and take them seriously.
Tip 3 : Talk about a relevant incident that made you keen on the profession you are pursuing and follow up by discussing your education.