Board s(int num, Board b)
{
if (num > 81 || b.checkComplete())
{
return b;
}
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
if (b.get(i, j) == 0)
{
for (int n = 1; n < 10; n++)
{
if (!existInRow(b, j, n) && !existInCol(b, i, n) && !existInZone(b, i, j, n))
{
int[,] copy = (int[,])b.getArray().Clone();
b.set(i, j, n);
Board tmp = s(num + 1, b);
if (tmp != null)
{
return tmp;
} else
{
b.set(copy);
}
}
}
return null;
}
}
}
return b;
}
bool existInRow(Board b, int y, int val)
{
for (int i = 0; i < 9; i++)
{
if (b.get(i, y) == val)
{
return true;
}
}
return false;
}
bool existInCol(Board b, int x, int val)
{
for (int i = 0; i < 9; i++)
{
if (b.get(x, i) == val)
{
return true;
}
}
return false;
}
bool existInZone(Board b, int x, int y, int val)
{
int[] zonesLimits = new int[] { 0, 0, 0, 3, 3, 3, 6, 6, 6 };
for (int i = zonesLimits[x]; i < zonesLimits[x] + 3; i++)
{
for (int j = zonesLimits[y]; j < zonesLimits[y] + 3; j++)
{
if (b.get(i, j) == val)
{
return true;
}
}
}
return false;
}
