Project Euler

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Project Euler is an English language website. It contains a number of problems that can be solved using math and programming. The target audience of the site are people who participate in mathematics are interested and algorithmic efficiency and apply their knowledge and want to expand.

Project Euler was founded in October 2001 by Colin Hughes. His motivation is "to offer the inquiring mind a platform to delve into unfamiliar areas and learn new concepts in an entertaining context". The page contains 722 problems (as of July 2020) in different degrees of difficulty. The problems are designed in such a way that an efficient algorithm run on a moderately powerful computer can solve them in a minute. As soon as a registered user has entered the correct result, he is given access to a discussion thread on this problem, in which the users can present their different solution strategies. He can bring experience from solving simple problems and the discussed solution strategies of other users to solving more difficult problems.

The website is free of charge and can be used without registering, but free registration is required to check the results and participate in discussions.

According to their own statements, the users come from 219 countries, with the majority of users coming from English-speaking countries and Europe. There are said to be around 1,027,375 registered users who have solved at least one of the problems (as of July 2020).

Some sample problems

Project Euler's first problem is:

"If we list all the natural numbers under 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these numbers is 23. Find the sum of all multiples of 3 or 5 under 1000."

While this problem can still be solved with basic school mathematics and a few basic operations in the respective programming language, solving other problems requires a very advanced knowledge of mathematical and computer science concepts, such as data structures , graph theory , number theory and the development of efficient algorithms .

In problem 25 the program has to develop the Fibonacci sequence until the number is 1000 digits long. This overwhelms the available data types in most programming languages ​​by far. For example, the maximum value of a 32-bit unsigned integer is 4,294,967,295 (10 digits), while with 64 bit, twenty decimal places are possible. The written addition from school mathematics, which can handle an unlimited number of decimal places, must be transferred to a computer program.

Problem 349 concerns Langton's ant :

“An ant moves on a grid, the fields of which are either white or black. The ant moves from one field to another in four directions (left, right, up, down) according to the following rules:
  1. when the ant arrives on a black field, the color of the field changes to white, the ant turns 90 degrees to the left, and visits the next field;
  2. when the ant arrives on a white field, the color changes to black, the ant turns 90 degrees to the right, and visits the next field.
If the ant starts on a grid with completely white boxes, how many fields are black, after the ant 10 18 made trains? "

Here the question arises, for example, how the grid with the black / white information must be saved and how the grid, once saved, can grow if the ant arrives at the edge of the grid.

Programming languages ​​used

The registered participants can indicate which programming language they use to solve the tasks. In October 2017, the ten most popular programming languages ​​were Python , C / C ++ , Java , C # , Haskell , Ruby , PHP , Matlab , Perl, and Scala , in descending order . The first four accounts for 74% of all registered users, the ten most popular languages ​​87%, while the two scientific tools Mathematica and R account for 0.96% and 0.63%, respectively.

Temporary shutdown in 2014

On June 16, 2014, the Project Euler site was shut down and replaced by a notice stating an unspecified security problem as the reason. On June 22nd, a break-in and possible theft of the password database table was admitted. From June 27th, the information function could be used again. On August 16, 2014 the site went online in a completely new implementation. Among other things, there is now no need to save email addresses.

Web links

Individual evidence

  1. ↑ projecteuler.net
  2. ^ Colin Hughes: Recent Problems - Project Euler. Retrieved December 31, 2017 .
  3. ↑ projecteuler.net (only accessible for registered users)
  4. ↑ projecteuler.net (only accessible for registered users)
  5. ↑ projecteuler.net (only accessible for registered users)
  6. ↑ Problem 1
  7. ↑ [1]
  8. ↑ https://projecteuler.net/languages
  9. ↑ projecteuler.net