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by xondono 2294 days ago
Alice and Bob just need to agree before hand on the proper distribution of 1s:

Alice will set the combination 100 if she was assigned either the first or the second rows, and the 010 if she is assigned the last.

Now Bob knows how to win if he gets first column since 110 will always win, and knows how to win if he gets the last column, because 000 always wins.

When assigned the middle column though, he needs to choose between 101 and 011. He will win if Alice got last row no matter what, but the other two are a toss up.

He’ll get it right half of the time, so he will win for sure if row and column meet at 7/9 squares, and the other two he’ll win half of the time, thus 8/9.