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Technological Thoughts by Jerome Kehrli

Entries tagged [programming]

Sudoku Laboratoy

by Jerome Kehrli


Posted on Tuesday Aug 30, 2016 at 09:02AM in Computer Science


I have written a little Sudoku program for which I provide here the source code and Windows pre-built executables. Current version is Sudoku 0.2-beta.

It supports the following features:

  • A GUI to display and manipulate a Sudoku board
  • A Sudoku generator
  • A Sudoku solver
  • A Sudoku solving tutorial (quite limited at the moment)

Sudoku Laboratory - Screenshot 1 Sudoku Laboratory - Screenshot 2
At the moment there are two resolution methods supported, one using human-like resolution techniques and a second using backtracking. The resolution of a solvable Sudoku board takes a few milliseconds only.
A solvable Sudoku board is a Sudoku board than has one and only one solution.

The Sudoku board generator generates solvable Sudoku boards. It usually generates boards between 18 and 22 pre-filled cells. (which is quite better than most generators I could find online).
Currently it generates the best (i.e. most difficult) board it possibly can provided the random initial situation (with all cells filled) of the board.
The problem I'm facing in this current version is that it can take from a few seconds only up to several minutes to generate the board (this is discussed in the algorithms section below).
In addition, the difficulty of the resulting board is not tweakable at the moment. In some cases it generates an extremely difficult board (only solvable with nishio) in a few seconds while some other times it needs two minutes to generate an easy board.

The software is written in C++ on Linux with the help of the wxWidgets GUI library.
It is cross-platform to the extent of the wxWidgets library, i.e. it can be compiled on Windows, OS X, BSD, etc.

A makefile is provided to build it, no configure scripts, i.e. you need to adapt the makefile to your own Linux distribution (or on Windows Mingw, TDM, etc.).
Happily only few adaptations should be required.

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Functional programming in Haskell

by Jerome Kehrli


Posted on Sunday Jan 24, 2010 at 05:28PM in Computer Science


Functional programming addicts,

I'm following an Haskell programming course. It was a short course, though we ran pretty much completely through the book "Programming in Haskell" by Graham Hutton. My personal view on this is that Haskell is a great language which offers a concision rarely reached by other languages, even other functional ones. The book sucks though. It's follows a way too much theoretical approach which makes it quite cumbersome and not interesting at all.

I've been told though that Hutton's book is the reference for Haskell programming. On my side I really found the various tutorials I could find online much more useful than the thorough lecture of this book I've been pretty much forced to follow.

Anyway, as usual I made a nifty summary on this book, so help yourself :

Haskell summary

The summary stands on three A4 pages and should serve as a reference for those who are initiated to Haskell programming and seek for a quick programming reference.

Happy reading, HTH