HackerEarth Challenge - Chess App

Content

• Problem Statement
• Requirements
• Demo
• Minimum Requirements Of Project
• Plus Point
• Extra Work
• Guide
• Expectation
• How to make them play against each other
• Explanation on Elo rating system
• Installation
• Contributing
• Credits
• License

Problem Statement

A pseudo iOS application which would let users list top 20 rated chess players of all-time and play them against each other using a random function.

Requirements

• iOS 9.0+
• Xcode 7.0

Demo

Screenshots

Minimum Requirements Of Project

• Players details. Use the url mentioned below which contains the JSON consisting of details.

• Visually interactive design to list Players.

• Write a function to select two players of your choice and play them against each other.

• Submit Source code, Screenshots & detailed deployment instructions.

Plus Point

• Make beautiful information intensive graphs.

• Represent statistics of a match in those graphs.

• Implement paging to display the players list properly.

• Feel free to use your favourite iOS Development SDK and tools in development and design.

Extra Work

• Display the probability of win of a particular player against a stronger opponent in a graph.

• Custom design, font and icons to make app more user-friendly.

• You may add portfolio activity comprising awesome work you have done in iOS.

• Use your imagination and add features which would make things easier for end users.

• Beautify; Comment; Documented code; handle Input Exceptions, Unicode and Null values.

Guide

• Mokriya Battle of Legends Data Url: API URL

• iOS JSON: REST API PARSE JSON SWIFT

Expectation

• You are expected to fetch top-rated player details from the provided url, list them based on their rating.

• Allow users to select any two of them and play them against each other.

• Display results on a pie chart or any graph, calculate their new rating using Elo rating system (with 'n' = 400 and k-factor = 32) and update their new rating locally.

• Display their updated rating on the UI.

How to make them play against each other

• Use a random function from range 1 to 3. If it generates 1, player 1 wins and gets 1 and player 2 gets 0. If it generates 2, player 2 wins and gets 1 and player 1 gets 0. If it generates 3, match is drawn and both get 0.5.

Explanation on Elo rating system

• Suppose two players with the current ratings r(1) and r(2) compete in a match. Calculate their updated rating r'(1) and r'(2) after said match.

• Take 'n' = 400 and k-factor = 32.

• The first step is to compute the transformed rating for each player or team:

R(1) = 10r(1)/400

R(2) = 10r(2)/400

• This is just to simplify the further computations. In the second step we calculate the expected score for each player:

E(1) = R(1) / (R(1) + R(2))

`E(2) = R(2) / (R(1) + R(2))``

• Now we wait for the match to finish and set the actual score in the third step:

S(1) = 1 if player 1 wins / 0.5 if draw / 0 if player 2 wins

S(2) = 0 if player 1 wins / 0.5 if draw / 1 if player 2 wins

• Now we can put it all together and in a fourth step find out the updated Elo-rating for each player:

r'(1) = r(1) + K * (S(1) – E(1))

`r'(2) = r(2) + K * (S(2) – E(2))``

• As a result, plot this r’(1) and r’(2) in a graph relatively.

Installation

1. Download the zip or clone the repo to your desired directory.

$ git clone https://github.com/aashishtamsya/HackerEarth-Challenge.git

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request. 😉 😊

Credits

Aashish Tamsya @ChiefAashish, aashish.tamsya@gmail.com

License

The content of HackerEarth Challenge itself is licensed under the Creative Commons Attribution 3.0 license, and the underlying source code used to format and display that content is licensed under the MIT license.

See the LICENSE file for more info.