Sudoku solver

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See also - Introduction to sudoku | Solving sudoku

What is the Sudoku solver?
The Sudoku solver  is program written for Microsoft Excel, which, when a puzzle is entered, will attempt to find a solution to that puzzle as quickly as possible.
sudoku_solver.xls
File Size: 1252 kb
File Type: xls
Download File

(Version 4.10, 1.18MB)

What does the Sudoku solver do?

You begin by entering a Sudoku puzzle. The program will then...
  • Attempt to solve the puzzle using logic, and if necessary, guessing,
  • Inform you if the puzzle cannot be solved,
  • Inform you if the puzzle requires guessing to be solved,
  • Inform you if the puzzle has more than one solution,
  • Show you the solution to the puzzle, with the original clues highlighted for clarity,
  • Let you save up to 25 puzzles to load into the solver at any time.

Below are some screenshots from the program...


You enter your puzzle...
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You then hit the solve button, and the program solves it for you.
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A shot of where you can enter up to 25 puzzles to automatically load into the solver.
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How does the Sudoku solver work?
The program first attempts to solve the puzzle using logical processes. These processes are identical to the ones I use myself when solving the puzzles on paper, which, to date, have not failed me (see solving sudoku for more on the processes involved). If no solution can be established by logic, the program goes on to guess at numbers, guessing at the squares with the fewest options first. The guessing procedure will always yield at least one solution to the puzzle. If the puzzle has no solutions, then the program will realise this while still in the logic stage.


Where did you get the information to write the Sudoku solver?

As I said, the methods the program uses to solve the puzzles are based on how I myself solve the puzzles, so all the program's code is my own work. The preprogrammed puzzles in the solver come from The Times newspaper (from 13 - 17 July 2006) and sudoku.org.uk (July 16 2006).


If this page makes little sense to you, you may find my introduction to sudoku useful.


Page last updated on 26th July 2009 at 21:04 UT
This page copyright 2006-9 Matthew Skues