OJ Board

Here is example:
****o**
*oo****
*oo*ooo
**o*ooo
****ooo
There is no '*' with 0/1 unmarked adjacent '*'. So select an arbitrary unmarked '*' with 2 unmarked adjacent '*'.
a***o**
aoo****
*oo*ooo
**o*ooo
****ooo
And so on by greedy algorithm:
1223o*5
1oo3445
*oo6ooo
99o6ooo
8877ooo ...

Greed Algorithm: at each step choose the point of interest not covered which is adjacent to the biggest amount of points of interests which are not yet covered. If there is more than one point of interest with the same minimum, choose one arbitrarily.

This point chosen, select arbitrarily one of ...