Determining the favored penny on a chessboard
Solution 1:
What I'll do is that:
- I will decide with my friend that we map the board from top-left to bottom-right from 0 to 63
- I'll decide with him that we count only Tails (Heads also will work :-) )
- Now what we'll do is XoR between all the Tails and get a result
- Flip the coin that needed to fix the XoR to the wanted square - your penny
Example: lets say that there are tails only on 3,7,20,61 and the chosen sqare is 8: XoR on them {3,7,20,61} will be: 45. now what number XoR 45 will give us 8? 37!! I'll flip 37 :-)
that's it...