Improve Programming And Coding Skills

1. HackerRank :

The HackerRank Community is one of the largest learning and competition community for programmers. They have exercises related to Python, Java, SQL, C++, Linux Shell and lots more.  You will be able to learn new programming topics and techniques by going through the challenges on HackerRank. Many challenges will also involve a competition between your bots and the bots coded by other hackers, so may the best hacker win

2. HackerEarth :

HackerEarth is an online skill assessment tool for conducting programming tests to evaluate developers. Supports almost all famous programming languages.

3. CodeChef :

CodeChef was created as a platform to help programmers make it big in the world of algorithms, computer programming and programming contests. It is a not-for-profit educational initiative by Directi, an Indian software company and a global programming community that fosters learning and friendly competition.

4. Exercism :

Exercism is another tool to level up your programming and coding skills. Exercises are suitable for both code newbies and experienced programmers. You can download and pratice problems over 30 different programming languages.

5. Codeforces :

Codeforces is a Russian website dedicated to competitive programming. They provide different mode of services like — participation in the short (2-hours) contests, challenge/hack other contestants solutions, ability to solve problems from previous contests for training purposes and many other.

6. Sphere Online Judge (SPOJ) :

SPOJ (Sphere Online Judge) is an online judge system with over 200,000 registered users and over 20,000 problems. Tasks are prepared by its community of problem setters or are taken from previous programming contests. SPOJ allows advanced users to organize contests under their own rules and also includes a forum where programmers can discuss how to solve a particular problem.

7. CodingBat :

CodingBat is a free site of live coding problems to build coding skill in Java and Python. CodingBat problems work great as homework, or for self-study practice, or in a lab, or as live lecture examples. 

8. Project Euler :

Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.

9. CodeEval :

CodeEval is a platform used by developers to showcase their skills. Developers can participate in app building competitions and win cash/prizes. They can also solve programming challenges as a way to impress employers with their technical skills.

10. TopCoder :

Topcoder is one of the world’s largest community of competitive designers, developers, and data scientists. Topcoder hosts fortnightly online competitive programming competitions—known as SRMs or “single round matches”—as well as weekly competitions in graphic design and development.

11. Google Code Jam :

Google Code Jam is an international programming competition hosted and administered by Google. The competition consists of a set of algorithmic problems which must be solved in a fixed amount of time. Competitors may use any programming language and development environment to obtain their solutions.

12. LeetCode Online Judge :

LeetCode OJ is a platform for preparing technical coding interviews. Pick from an expanding library of more than 190 questions, code and submit your solution to see if you have solved it correctly. Supports 9 programming languages: C, C++, Java, Python, C#, JavaScript, Ruby, Bash, MySQL.

That’s it enrich your programming and coding skill with the help of these websites and also don’t forget to share it with your coder buddy.

How To Set-up VPN on Android Devices (No Software Needed)

With hackers and in fact sometimes our own governments lurking around, looking for just one opportunity to steal your data, you might want to give serious reconsideration before connecting. Somehow the idea of my bank credentials and personal information resting in someone else’s hands doesn’t seem to be very enthralling to me.

So how to overcome this problem? Simple just configure a Virtual Private Network (VPN).

 

A VPN would allow you to connect your device up to a secure connection to another network over the internet. In fact you can use it to access your home/company network while you are away, download apps which are not available in your country or simply keep your browsing and data secure over the public network.

So here is how to go about setting a VPN on your Android device:

Step 1. Go to Menu > Settings

Step 2. Now Click on More

Step 3. Now click on VPN and a screen like this one would open up:

Step 4. Now tap on the ‘+’ button at the right corner of the screen:

Step 5. Here enter a Name for the VPN connection, select the type of VPN server you are connecting to and enter the VPN server’s address and then click save.

Step 6. Now just tap on the created VPN to connect. You will be prompted to enter a username and password. After entering which you can connect to the VPN.

Once you are connected you will see a Key Icon / “VPN activated” notification in the notification drawer. In case you want to disconnect, simply tap on the notification and tap Disconnect.

Bonus Tip: In case you want to ensure that your data is always sent over a VPN, for instance while using a public Wi-Fi network all you need to do is this:

Connect to a VPN, save your account information and then click on the three dots icon at the corner of the screen. After that click on the ‘Always-On VPN’ icon to access this feature.

Note: I would advise readers to change their Screen Lock over from ‘Slide’ to ‘Pin’ or ‘Password’ otherwise they might get this error:

Also, sometimes you might be prompted with this:

Be careful because randomly entering passwords may cause your credential storage to be erased.

Now there is absolutely no need to freak out. Here is where our first tip would come in handy, just simply change your PIN and the question will go away as the credentials would have been forced to be updated.

Switch Vs Router: Differences And Comparison Of Their Working Functionalities

Switches are very popular as a layer two device whereas a router is very famous for being a layer three device. So, what is that something special that makes router the most popular layer three device? We will take a look at all the differences and functional aspects of a switch and a router

Let’s take a look:

Switch vs Router — Comparison and differences

Switch’s properties:

Works at the Data link layer of the OSI layerUses ‘filter and forwarding’ when it receives a data packet in form of a frameA virtual LAN can be created using a Switch which inside the same LAN separates the LANs and make them virtual to each otherUsually comes with 24 to 48 portsTransmits Frames (layer 2 packets) and Layer 3 packets of the OSI modelUses its software for admin access and other configurationsHas its own memory for memorizing the devices connected over to the networkCan learn the MAC addresses and stores those addressed in a CAM (Content Addressable Memories)Supports Half as well as full duplex transmission modeA hub has only one broadcast domainCan support Spanning tree protocolNo packet collisions occur commonly inside a SwitchNo dynamic sharing of the bandwidth

Router’s properties:

Connects more than two networks unlike a SwitchWorks as a traffic police to direct a data packetCan be used for LAN, MAN, and WANIts packet is called a packet unlike a frame at layer two and electrical signal at layer oneIt works at layer three or also known as network layer of the OSI layerIt usually has 2-4-8 portsIt also stored Ip addresses in a table called Routing table and from there, it decides where to send the data packetIn router, every port has its own broadcast domainDynamic bandwidth sharingFaster processing than a switchCan perform Network Address Translations (NAT)

Working differences — Switch vs router

Before you proceed to further reading, have a look at the basic concepts of the different networking devices and hardware types — hub, switch, router, modem, bridge, repeater.

Let’s say around fifty computers are connected in a local area network. In the network, there is also a common resource from where computers can download data locally. So, this network forms a kind of a private network. However, when one of the computers would want to get some data from online sites like Facebook or Google, they will have to go to the internet and fetch the data and that makes a public network

So, when a computer wants to access a public network, it sends a data packet to the Switch which is the next immediate device in terms of data transmission. The switch opens up the packet and looks for the destination where the request packet wants to go.

The packet is directed for the public internet or world wide internet and Switch has no idea about it. So, Switch forwards this packet to the router — ‘The default gateway’. A router works as a gateway that is more like it is a door to the outside world and gets the data that a particular computer wants.

However, inside the campus, all the computers are a part of the private network which is not known to the outside world. So, it tweaks the private packet into the public packet and vice versa. This is called NATting which we will cover in the later topics.

What Is HTTP/2 And How It Works

HTTP 1.1 was a major move from HTTP 1.0 as it allowed persisted connections (more than one request/response on the same HTTP connection), improved caching, new status code, Enhanced compression support, OPTION method for Cross Origin Resource Sharing in web application and much more.

HTTP/1.1 has served the Web well for more than fifteen years, but its age is starting to show. Loading a Web page is more resource intensive than ever, and loading all of those assets efficiently is difficult because HTTP practically only allows one outstanding request per TCP connection.

Because of which, many TCP connections are created to issue parallel requests. And since there isn’t any limit on this; too many connections are used most of the times which leads to TCP congestion and unfair resource usage by browsers. It also means lots of duplicate data being transferred “on the wire”.

If too many requests are made, it hurts performance. This has led the industry to a place where it’s considered Best Practice to do things like spriting, data: inlining, domain sharding and concatenation. These hacks are indications of underlying problems in the protocol itself, and cause a number of problems on their own when used.

HTTP/2, on the other hand, enables a more efficient use of network resources and a reduced perception of latency by introducing header field compression and allowing multiple concurrent exchanges on the same connection. It also introduces unsolicited push of representations from servers to clients. This specification is an alternative to, but does not obsolete, the HTTP/1.1 message syntax. HTTP’s existing semantics remains unchanged.

At a high level, HTTP/2:

is binary, instead of textualis fully multiplexed, instead of ordered and blockingcan, therefore, use one connection for parallelismuses header compression to reduce overheadallows servers to “push” responses proactively into client caches

Difference Between HDMI, VGA, DisplayPort, DVI, Thunderbolt, And MHL

If you want to connect your laptop to your TV or monitor, the most common thing to go for is HDMI. However, there are other cable options like DisplayPort, DVI, Thunderbolt, and VGA which are in existence since almost three decades.

All these different interfaces have been designed to carry video signals (and audio signals) from one device to another. So, what’s the thing which sets them apart? If you’re thinking it’s the video quality, then you might be correct only in the case of VGA. As for other connection interfaces, the video quality is almost the same.

VGA

It stands for Video Graphics Array and it’s probably the oldest display connector which can still be seen on a number of devices. I have a VGA port on my old Dell Inspiron. But the VGA connector, for obvious reasons, has started to lose its place on various devices for more advanced technologies. HDMI is an alternative in most cases. For Apple, Intel’s Thunderbolt is the interface used to push video content out of their laptops to display device.

VGA was originally created in the year 1987 by IBM as a display hardware. But it is widely recognized by people as the 15-pin D-Sub connector on the desktop machines which comes with screws to lock the connector with the VGA port.

VGA can support a video resolution of 1080p (and higher), but that’s not the thing which can help it to compete against newer technologies. This is because VGA uses analog signals to carry video from source to the receiving device. And it contributes to a degraded picture quality, often visible when compared to other interfaces based on digital signals.

A separate audio connection is required if you want to throw videos using VGA cables as it lacks support for the same. The length of the VGA cable, in addition to the quality of the material, can affect the intensity of signal degradation. Moreover, a low-quality VGA cable may also suffer from signal crosstalk or ghosting, in which signals from other wires in the vicinity can introduce unwanted currents.

DVI

Digital Visual Interface is the one to follow the legacy of the VGA connector, but by taking the digital path. DVI, created by Digital Display Working Group, was introduced in the year 1999. The 29-pin connector shares visual traits with VGA connector and sports the screw locks.

DVI interface can push uncompressed digital video streams to a receiving device. In the case of digital signals, it can support WUXGA (1920x 1200) resolution @ 60 Hz via Single Link, and WQXGA (2560 x 1600) @ 60 Hz via Dual Link.

DVI also supports analog video output which makes it backward compatible (using an adapter) with the VGA interface. DVI might be relatively newer than VGA, it has mainly found its place on computer monitors. However, the technology is also on the verge of extinction.

DisplayPort

Launched in 2006, DisplayPort is a lot younger in comparison to VGA and DVI, and even HDMI. It is backward compatible with these interfaces. Just like DVI, it is primarily intended to be a computer connection interface.

According to the newest DisplayPort 1.4 specifications, it can support HDR and up to 8K video output on compatible devices. It also deploys a something known as Display Video Compression, which is claimed to deliver visually lossless video over a DisplayPort connection. Nvidia’s GeForce GTX 1080 is the world’s first graphics card to feature DisplayPort 1.4.

VESA, the creator of DisplayPort wants to put it as a considerable option for audio/video connection. They’re constantly adding support for various technologies to maintain pace with HDMI. Dynamic metadata support is available with DisplayPort 1.4 for HDR-compatible devices. It allows content creators to configure HDR for individual scenes.

An advantage of using a digital video connection is the implementation of DRM to prevent unauthorized playback of copyrighted content. Earlier versions of DisplayPort added support for DPCP (128-bit AES encryption), but the 56-bit HDCP was favored with the release of DisplayPort 1.1. Now DisplayPort 1.3 comes with HDCP 2.2.

DisplayPort comes with various other perks. A variant known as DisplayPort++ (or Dual-Mode) can be used to throw out HDMI and DVI-compatible video content using the same hardware. Also, VESA has figured out a method to use Type-C USB as a DisplayPort output source. It is known as DisplayPort Alternate Mode, and it doesn’t require any adapter. So, if you are among the ones who purchased the single port Macbook, then you should be thankful to that particular port.

Furthermore, DisplayPort can produce output for more than one monitors using a single port. Multiple monitors can be added either by daisy chaining or using a hub.

HDMI

High-Definition Multimedia Interface is a proprietary video interface. You can find HDMI ports on almost every consumer electronics including televisions, monitors, DVRs, music systems. etc. HDMI 2.0 supports video output resolutions up to 4K (4096 x 20160p @ 60Hz). Future version i.e. HDMI 2.1 might arrive with support for an 8k resolution.

An HDMI hub or splitter can be used to deliver video output to multiple monitors. But daisy chaining in the case of HDMI is not an easy task in comparison to DisplayPort. Since, the release of HDMI 1.3, it has started to feature an Ethernet link (capable of transferring data at 100Mbps) in the cable itself. Another notable HDMI feature is ARC (Audio Return Channel) which enables transfer of audio from a source (television etc) to a receiver (for instance, connected speakers). Earlier, it was done using a sperate audio cable.

Talking about cables, they come in standard and high-speed cable options, both with and without an ethernet link. HDMI also implements content protection via HDCP. Moreover, a single remote control can be used to control various CEC (Consumer Electronics Control)-enabled devices connected over HDMI.

Similar to DisplayPort, an Alternate Mode using Type-C USB can be used to connect an HDMI-compliant device to a receiving device.

Thunderbolt

It’s an Intel-designed multipurpose interface which is intended for video output as well as connecting storage devices. Other than display, you can find a number of hard drives and SSDs using Thunderbolt port for connection. Thunderbolt isn’t present on many devices as it has been in existence since the last five years only. Apple was quick to put Thunderbolt ports on its Macbook Air and Pro laptops.

Earlier versions of Thunderbolt (1 & 2) interface utilized the mini DisplayPort connector. In the case of Thunderbolt 3, USB Type-C is used as the connector.

Thunderbolt 3 supports a maximum theoretical bandwidth of 40Gbit/s, capable of pushing video streams on two 4K displays at the same time. A single Thunderbolt port can connect up to 6 devices via daisy-chaining or a hub. By using the Type-C connector, it can also leverage the USB Power Delivery feature which can be used to charge a connected device using up to 100 watts of power.

MHL

Mobile High-Definition Link is an interface created for portable devices including mobile phones. MHL can be thought of as a spin-off version of HDMI. It was first proposed by Silicon Image which also had a significant contribution in the development of HDMI.

The initial version of MHL was capable of delivering 1080p video output along with eight channel audio. It also had features like HDCP and could be used to control CEC-enabled devices.

MHL 3 introduced support for 4K 30fps videos along with HDCP 2.2 and improved 7.1 surround audio. On mobile devices, it uses the micro-USB 2.0 port to connect to a display device using an MHL to HDMI adapter.

The latest version, superMHL, adds support for 8K videos at 120fps, Dolby Atmos, HDR, etc. It also brings a new reversible superMHL connector into the picture. Also, you can connect multiple displays to a single superMHL port. Just like HDMI, DisplayPort, and Thunderbolt, there is an MHL Alternate Mode for USB Type-C.

Winding Up

So, these were some of the interfaces designed to send audio/video content from one device to another. Clearly speaking, for VGA and DVI, most of their territory is acquired by newer alternatives, namely HDMI and DisplayPort.

If we try to compare DisplayPort and HDMI, DisplayPort may have an upper hand in the specifications department, but the reality is that HDMI has already captured most of the market. And now, makers of DisplayPort have started pushing their technology in the consumer space. Otherwise, DisplayPort has been mainly present on monitors and graphics cards.

Intel’s Thunderbolt is yet to make an impact. But thanks to the companies who have started giving Thunderbolt a place on their devices. Similarly, MHL has also existed for a small amount of time, but its utility in small devices, often compromising on space, has helped it speed on the success route.

For the time being, you can stick to HDMI for most of the time. But MHL is also touting itself as a promising technology for the future. And so is the case of DisplayPort. Intel Thunderbolt is posing itself as a one-stop solution for your various connection needs. Above all, a sense of relief is the implementation of USB Type-C for these different interfaces, which can also eliminate the requirement of different ports on a single device.

How to Erase Your Web Accounts in One Click

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