I've got a naive algorithm figured out using this general strategy.
For a given row or column; let the Reward associated with it be the following:
Reward = (# of total coins - # of total uncovered coins) - (# of covered squares - # of total Voltorb squares)
So for a completely uncovered row with 1 total coin and 4 Voltorbs, the reward is:
Reward = (1 - 0) - (5 - 4) = 0
Similarly, a column with one square flipped that was a 3 with 5 total coins and 2 Voltorbs:
Reward = (5 - 3) - (4 - 2) = 0
And just for kicks, a row with 9 total coins, 1 Voltorb, and 1 square uncovered showing a 2:
Reward = (9 - 2) - (4 - 1) = 4
Here's where the naive approach comes in. Since you "win" Voltorb Flip by uncovering all the x2 and x3 squares, you can naively assume that the square with the highest total Reward both row-wise and column-wise is the best square to uncover. I wrote an online Voltorb Flip Helper that uses this algorithm to determine the best space to uncover. The "Hybrid" option also takes into account the risk of uncovering a square: if a row of 5 uncovered squares has 4 Voltorbs total in it, there's only a 20% chance of surviving the flip. So even if the reward for uncovering the one safe square is 3, it might not be in your best interest to go for it.
As for eliminating certain combinations altogether, consider this problem: assuming an American Football scoring system where you can only score field goals (3 points) or touchdowns (7 points), what is the highest possible unattainable score, if there is a maximum?
For a given row or column; let the Reward associated with it be the following:
Reward = (# of total coins - # of total uncovered coins) - (# of covered squares - # of total Voltorb squares)
So for a completely uncovered row with 1 total coin and 4 Voltorbs, the reward is:
Reward = (1 - 0) - (5 - 4) = 0
Similarly, a column with one square flipped that was a 3 with 5 total coins and 2 Voltorbs:
Reward = (5 - 3) - (4 - 2) = 0
And just for kicks, a row with 9 total coins, 1 Voltorb, and 1 square uncovered showing a 2:
Reward = (9 - 2) - (4 - 1) = 4
Here's where the naive approach comes in. Since you "win" Voltorb Flip by uncovering all the x2 and x3 squares, you can naively assume that the square with the highest total Reward both row-wise and column-wise is the best square to uncover. I wrote an online Voltorb Flip Helper that uses this algorithm to determine the best space to uncover. The "Hybrid" option also takes into account the risk of uncovering a square: if a row of 5 uncovered squares has 4 Voltorbs total in it, there's only a 20% chance of surviving the flip. So even if the reward for uncovering the one safe square is 3, it might not be in your best interest to go for it.
As for eliminating certain combinations altogether, consider this problem: assuming an American Football scoring system where you can only score field goals (3 points) or touchdowns (7 points), what is the highest possible unattainable score, if there is a maximum?