Software Engineer

Sorting can be used to solve this problem. Next, two -pointer technique can be applied on the sorted array.
Traverse the array and fix the first element of the triplet. Now use the Two Pointer technique to find if there is a pair whose sum is equal to x – array[i].

Algorithm : 
1. Sort the given array.
2. Loop over the array and fix the first element of the possible triplet, arr[i].
3. Then fix two pointers, one at i + 1 and the other at n – 1. And look at the sum, 
1. If the sum < required sum, increment the first pointer.
2. Else, If the sum > required sum, Decrease the end pointer to reduce the sum.
3. Else, if the sum of elements at two-pointers == required sum, then print the triplet and break.

Time Complexity : O(nlogn)

A stack can be used to solve this question. 
We traverse the given string s and if we:
1. see open bracket we put it to stack
2. see closed bracket, then it must be equal to bracket in the top of our stack, so we check it and if it is true, we remove this pair of brackets.
3. In the end, if and only if we have empty stack, we have valid string.
Complexity: time complexity is O(n): we put and pop each element of string from our stack only once. Space complexity is O(n).

1. The browser extracts the domain name from the URL.
2. The browser queries DNS for the IP address of the URL. Generally, the browser will have cached domains previously visited, and the operating system will have cached queries from any number of applications. If neither the browser nor the OS have a cached copy of the IP address, then a request is sent off to the system's configured DNS server. The client machine knows the IP address for the DNS server, so no lookup is necessary.
3. The request sent to the DNS server is almost always smaller than the maximum packet size, and is thus sent off as a single packet. In addition to the content of the request, the packet includes the IP address it is destined for in its header. Except in the simplest of cases (network hubs), as the packet reaches each piece of network equipment between the client and server, that equipment uses a routing table to figure out what node it is connected to that is most likely to be part of the fastest route to the destination. The process of determining which path is the best choice differs between equipment and can be very complicated.
4. The connection is either lost (in which case the request fails or is reiterated), or makes it to its destination, the DNS server.
5.If that DNS server has the address for that domain, it will return it. Otherwise, it will forward the query along to DNS server it is configured to defer to. This happens recursively until the request is fulfilled or it reaches an authoritative name server and can go no further.
6. Assuming the DNS request is successful, the client machine now has an IP address that uniquely identifies a machine on the Internet. The web browser then assembles an HTTP request, which consists of a header and optional content. The header includes things like the specific path being requested from the web server, the HTTP version, any relevant browser cookies, etc.
7. This HTTP request is sent off to the web server host as some number of packets, each of which is routed in the same was as the earlier DNS query. (The packets have sequence numbers that allow them to be reassembled in order even if they take different paths.) Once the request arrives at the webserver, it generates a response (this may be a static page, served as-is, or a more dynamic response, generated in any number of ways.) The web server software sends the generated page back to the client.

Physical Layer
The lowest layer of the OSI Model is concerned with electrically or optically transmitting raw unstructured data bits across the network from the physical layer of the sending device to the physical layer of the receiving device. It can include specifications such as voltages, pin layout, cabling, and radio frequencies.

Data Link Layer
At the data link layer, directly connected nodes are used to perform node-to-node data transfer where data is packaged into frames. The data link layer also corrects errors that may have occurred at the physical layer.
The data link layer encompasses two sub-layers of its own. The first, media access control (MAC), provides flow control and multiplexing for device transmissions over a network. The second, the logical link control (LLC), provides flow and error control over the physical medium as well as identifies line protocols.

Network Layer
The network layer is responsible for receiving frames from the data link layer, and delivering them to their intended destinations among based on the addresses contained inside the frame. The network layer finds the destination by using logical addresses, such as IP (internet protocol). At this layer, routers are a crucial component used to quite literally route information where it needs to go between networks.

Transport Layer
The transport layer manages the delivery and error checking of data packets. It regulates the size, sequencing, and ultimately the transfer of data between systems and hosts. One of the most common examples of the transport layer is TCP or the Transmission Control Protocol.

Session Layer
The session layer controls the conversations between different computers. A session or connection between machines is set up, managed, and terminated at layer 5. Session layer services also include authentication and reconnections.

Presentation Layer
The presentation layer formats or translates data for the application layer based on the syntax or semantics that the application accepts. Because of this, it at times also called the syntax layer. This layer can also handle the encryption and decryption required by the application layer.

Application Layer
At this layer, both the end user and the application layer interact directly with the software application. This layer sees network services provided to end-user applications such as a web browser or Office 365. The application layer identifies communication partners, resource availability, and synchronizes communication.

1. Process means any program is in execution. Thread means segment of a process.
2. Process takes more time to terminate. Thread takes less time to terminate.
3. It takes more time for creation. It takes less time for creation.
4. It also takes more time for context switching. It takes less time for context switching.
5. Process is less efficient in term of communication. Thread is more efficient in term of communication.
6. Process consume more resources. Thread consume less resources.
7. Process is isolated. Threads share memory.
8. Process is called heavy weight process. A Thread is lightweight as each thread in a process shares code, data and resources.

To center a div horizontally on a page, simply set the width of the element and the margin property to auto. That way, the div will take up whatever width is specified in the CSS and the browser will ensure the remaining space is split equally between the two margins.
Here’s the CSS:
.center {
margin: auto;
width: 60%;
border: 5px solid #FFFF00;
padding: 10px;
}

Here’s the HTML:

This div takes up the width specified in CSS and the remaining space is split equally between the two margins.
 

The virtual DOM (VDOM) is a programming concept where an ideal, or “virtual”, representation of a UI is kept in memory and synced with the “real” DOM by a library such as ReactDOM. This process is called reconciliation.

The second phase in the lifecycle is when a component is updated. A component is updated whenever there is a change in the component's state or props.
React has five built-in methods that gets called, in this order, when a component is updated:
getDerivedStateFromProps()
shouldComponentUpdate()
render()
getSnapshotBeforeUpdate()
componentDidUpdate()
The render() method is required and will always be called, the others are optional and will be called if you define them.

The event loop is what allows Node.js to perform non-blocking I/O operations — despite the fact that JavaScript is single-threaded — by offloading operations to the system kernel whenever possible.
Features of Event Loop:
Event loop is an endless loop, which waits for tasks, executes them and then sleeps until it receives more tasks.
The event loop executes tasks from the event queue only when the call stack is empty i.e. there is no ongoing task.
The event loop allows us to use callbacks and promises.
The event loop executes the tasks starting from the oldest first.

NodeJs was built with the intention of supporting asynchronous operations.... and the fact is that the asynchronous operations have better performance and scalability when they are single-threaded over multi-threaded. This is the reason the NodeJs is single threaded.

The approach would be to think the max product that we could get on breaking a number N into two factors. This product can be represented by the following function : f = x(N-x). 
The maximum of this function is achieved when x = N/2. 
However, factors should be integers. Thus the maximum is (N/2)*(N/2) when N is even or (N-1)/2 *(N+1)/2 when N is odd.
When the maximum of f is larger than N, we should do the break.
(N/2)*(N/2)>=N, then N>=4
(N-1)/2 *(N+1)/2>=N, then N>=5
These two expressions mean that factors should be less than 4, otherwise we can do the break and get a better product. The factors in last result should be 1, 2 or 3. Obviously, 1 should be abandoned. Thus, the factors of the perfect product should be 2 or 3.
Next thing is 6 = 3 + 3 = 2 + 2 + 2, but 3 * 3 > 2 * 2 * 2, that is every triplet of 2 can be replaced with tuple of 3 for maximum product, so we will keep breaking the number in terms of 3 only, until number remains as 4 or 2, which we will be broken into 2*2 (2*2 > 3*1) and 2 respectively and we will get our maximum product.

We know that the minute and hour hand coincide every 65 minutes and not 60 minutes.
Also, the hour and minute hand coincide only once between 11 and 1 o’clock i.e. at 12 o’clock.
So, from both the above statements we can say that the two hands coincide exactly 11 times in a 12 hour span.
We have to find the number of times in a day so we have 24 hours in a day. Therefore,
The number of times the two hands coincide =2×11=22
times.

So, the number of times the two hands coincide in a day is 22 times.

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.