[computer-go] Fast Board implementation

[Łukasz Lew]

Pseudo liberties of a group is a sum of liberties of each stone,
example:

OOOOO
OXXXO
OX.XO
OXXXO
OOOOO

"X" group have 4 pseudo liberties.

If You merge two groups just add pseudo liberties.
If PL = 0 then group should be removed.

This is simple and sufficient :)

Lukasz
On 12/11/06, Don Dailey <drd at mit.edu> wrote:
>
>
> On Mon, 2006-12-11 at 18:22 +0100, Łukasz Lew wrote:
> > - pseudo liberties at top of union-set tree
>
>
> Refresh my memory on this.   I remember talking about this a long time
> ago.  A psuedo liberty is an upper bound on how many liberties there are
> for a given string, correct?   Sometimes a liberty gets counted twice or
> more?
>
> But if it goes to zero or one it's correct for any given string?
>
> Is the idea that it's lightning fast to update incrementally?
>
> - Don
>
>
>