Dijkstra’s algorithm is a graph algorithm which was invented by the Dutch computer scientist Edsger Dijkstra in 1959. The algorithm finds the shortest ways from one of the graph nodes to all the others.

The algorithm exists in many variants; Dijkstra’s original variant found the shortest path between two nodes but a more common variant fixes a single node as the “source” node and finds the shortest paths from the source to all other nodes in the graph, producing a shortest-path tree (wikipedia.org, 2002).

The algorithm works as follows: Continue reading →

Lee’s algorithm is a path finding algorithm and is one reasonable solution for maze routing. It’s usually used in computer design systems to create routes for wires on printed boards.

Let’s look at the use of the algorithm on these pictures.

We need to associate cell1 with cell2:

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Nowadays, mobile developers have to work with a large amount of screen resolutions. Earlier applications had to contain a lot of the same pictures with different sizes to make icons display correctly. A few years ago, the icon font toolkit called Font Awesome became very popular. It gives developers an opportunity to escape from the large amount of pictures and flexibly adapt their products to different screen resolutions.

So, let’s start with the creation of the icon font. To do this we will need images in SVG format and a free service. I will use glyphter.com, which allows the use of a lot of different icons for free.

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First, you should download the Python installer. Go to the official site python.org/downloads/ and download the latest version:

After the download, run it and follow the instructions of the wizard. The default installation path is C:\Users\%USERNAME%\AppData\Local\Programs\Python\Python35-32. You can change it using the “Customize installation” button. Don’t forget check the the box for “Add Python 3.5 to PATH”. Otherwise, you will have to do it manually. After it is done, click “Install Now”. Continue reading →

To start programming in Java, you first need to install the software environment on your computer.

1) Download the Java installer.

In this guide, I will show how to use the Fody tool to reduce the amount of the required program code, and the use of icon fonts and NcontrolView library for the manual drawing of interface elements.

Business Applications

The first thing you need to know is the definition of the business applications, and differences between them and other kinds of apps.

We usually divide applications into logical groups using such criteria:

– Interface complexity
– Usage of the OS features
– Frequency of the usage Continue reading →

Hello! In this guide, I’ll show you the program to check the balance of different types of parentheses in an expression using C++.

Idea for Implementation

Everything would be much simpler if we had to check only one type of parentheses. If it is required to check the balance of the parentheses of only one type, for example, “(“ and “)”, we can read all the symbols one by one, ignoring all the symbols except the braces. If it is an opening bracket we increase the counter by 1, and if it’s a closing bracket we reduce the counter by one. After the check, it’s easy to define if the expression is balanced. If the counter is bigger than zero, we have more opening brackets. But if it goes lower than zero, we can’t check further. So we will use the stack. Continue reading →

Hello! In this guide I’ll show you how to use BlueJ to create and run Java programs. My example will be with the Tic Tac Toe game.

Download and install BlueJ from the official website bluej.org:

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Long ago, when monitors were black and green and computers had 64 kilobytes RAM, the legendary game was created. It was called “Snake” and it still has a lot of clones on different devices: from desktop to smartphones and tablets. But the original textual implementation hasn’t been used for years. So in this guide, I want to show you the canonical implementation of the legendary game.

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