SuDoKu Generator

Jonauz · Posted: Tue Jan 15, 2008 3:08 pm Post subject: SuDoKu Generator

Hi everyone..
I tryed to make my one sudoku puzle generator. I don't know why, but it still not work.

I have seen that there is a lot of explaining about sudoku. Also tips, hints and so on.. But haven't found any normal source that would work, and it would be easy to understant for thouse who only trying to creat one.

So, hellp me in this. I'm a student, and tried to do SuDoKu, to get a better mark..

Jonauz · Posted: Tue Jan 15, 2008 3:12 pm Post subject: Here is a code of my work:

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
Random rnd = new Random();
int[,] bord = new int[100, 100];
int sk, salyga = 0, operacijuSK=0, netikraSal=0;

#region Kvadratelis
do
{
#region
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
bord[i, j] = 0;
}
}
#endregion
for (int x1 = 0; x1 < 3; x1++)
{
for (int y1 = 0; y1 < 3; y1++)
{
for (int i = x1 * 3; i < x1 * 3 + 3; i++)
{
for (int j = y1 * 3; j < y1 * 3 + 3; j++)
{
operacijuSK = 0;
do
{
sk = rnd.Next(1, 10);
operacijuSK += 1;
//System.Console.WriteLine(sk);
#region ROW
for (int b = 0; b < 9; b++)
{
if (sk == bord[i, b])
{
b = 10;
salyga = 0;
}
else salyga = 1;
}
#endregion
#region SQUARE
if (salyga == 1)
{
for (int x = x1 * 3; x < x1 * 3 + 3; x++)
{
for (int y = y1 * 3; y < y1 * 3 + 3; y++)
{
if (sk == bord[x, y])
{
x = 100;
y = 100;
salyga = 0;
}
else salyga = 1;
}
}
}
#endregion
#region COLUM
if (salyga == 1)
{
for (int a = 0; a < 9; a++)
{
if (sk == bord[a, j])
{
a = 10;
salyga = 0;
}
}
}
#endregion
#region
if (operacijuSK == 100)
{
System.Console.WriteLine(" 100 !");
salyga = 1;
netikraSal = 1;
x1 = 3;
y1 = 3;
i = 9;
j = 9;
}
else netikraSal = 0;
#endregion
}
while (salyga == 0);
bord[i, j] = sk;
//Console.Write(bord[i, j]);

}
//Console.WriteLine();
}

#region
for (int x = 0; x < 9; x++)
{
for (int y = 0; y < 9; y++)
{
System.Console.Write(bord[x, y]);
}
System.Console.WriteLine();
}
System.Console.WriteLine();
#endregion
}
}
} while (netikraSal == 1);
#endregion

}
}
}

Ruud · Site Admin

Hi,

there are a few problems in your code:

- the variable names are in Lithuanian Wink

- you're mixing up the dimensions, a Sudoku 9x9 requires an array bord = new int[9,9] and you should compare the iterator (operacijuSK == 81)

- regions are nice to structure large code files, but here you would probably get better marks by reorganizing your code into a few functions. It would certainly make the code more readable.

- Finally, the most important issue is that your generator has no backtracking. When you operate in forward mode only, at some point the program will hang because no number is allowed in the next cell. Backtracking allows you to take a step back if the generator gets stuck. To implement backtracking, you need a control structure other than your for loops. Also, you need to keep track of the sk (values) you already tried, so you know when all possibilities have been exhausted. An alternative to backtracking is a complete restart, but that is much slower.

Even with these changes, the program will be slow, because it will often have to backtrack or restart.

Ruud
_________________
Meet me at sudocue.net

Jonauz · Posted: Wed Dec 02, 2009 11:55 pm Post subject:

Thanks for your answer Wink

So if my code is not good enough, maybe there is some king of free source generator, that I could get, and learn from it?

wapati · Posted: Thu Dec 03, 2009 7:36 am Post subject: