OK, got a question now
It is bitwise operator related but be thinking about sudoku to put it in context.
I will be comparing three cells.
Cell a will have the definite number 7 in it (for example).
Cell b will have the definite number 5 in it.
Cell c will have the candidate numbers 1, 3, 5 and 7 in it.
They can all "see" each other (i.e. in the same box, row or column).
At the moment my loop runs and I end up so that...
Cell a = 7
Cell b = 5
Cell c = 1,3 (i.e. it has had 5 and 7 eliminated)
BTW (7 is actually 64 and 1,3 is actually 5 (bitwise)).
That's all very good and VERY quick but at the end I want to see what has been removed.
If I take a copy at the beginning so I have ...
origCell a = 7
origCell b = 5
origCell c = 1,3,5,7
How can I compare cell c and origCell c to see what has been eliminated?
cell c = 1,3 = 5 = 000000101
origCell c = 1,3,5,7 = 85 = 001010101
Ah, XOR! cell c XOR origCell c = 001010000 = 80
Is that right?
