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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Beauty is in the eye of the beholder (was: Are we ready...
<snip/>
> Hmmm. Is the following Dijkstra-ascribed permutation algorithm
> (implementation in Java purely my fault) beauteous or just way too clever?:
>
>
> public class Permuter extends Object
> {
> int m_level;
> int[] m_value;
> int m_permCt = 0;
>
> public Permuter(int size)
> {
> m_level = -1;
> m_value = new int[size];
> }
>
> public void permute()
> {
> visit(0);
> System.out.println("\nTotal permutations = " + m_permCt);
> }
>
> public void visit(int k)
> {
> m_level++;
> m_value[k] = m_level;
>
> if (m_level == m_value.length)
> {
> addPermutation();
> }
> else
> {
> for (int i = 0; i < m_value.length; i++)
> {
> if (m_value[i] == 0)
> visit(i);
> }
> }
>
> m_level--;
> m_value[k] = 0;
> }
>
> void addPermutation()
> {
> for (int i = 0; i < m_value.length; i++)
> {
> System.out.print(m_value[i] + " ");
> }
>
> System.out.println();
>
> m_permCt++;
> }
>
> }
>
> I have a hard enough time tracing through this in a debugger without getting
> lost. Works pretty fast, though, I will admit.
> >
at least i can read it....
one of the many reasons i don't use debuggers is that they are difficult
to drive in a recursive algorithm (we still teach those i hope). easier
to sit and think about what's really happening, run a couple of tests,
and move on.
;)
rick
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