Well it was given in the question that it is always possible..

I meant this:
Since the order of flipping doesn't matter, and making a move on a coin twice is like not making a move at all, we can just find all distinct combinations of flipping coins, and minimizing the size of good combinations(go od meaning those that give all tails).

This can be done by making a set consisting of all coins, each represented by an index.(i.e. if there were 20 coins in all, this set would contain 20 elements,...

This came in a competition:
There is a rectangular grid of coins, with heads being represented by the value 1 and tails being represented by the value 0. You represent this using a 2D integer array table (between 1 to 10 rows/columns, inclusive).

In each move, you choose any single cell (R, C) in the grid (R-th row, C-th column) and flip the coins in all cells (r, c), where r is between 0 and R, inclusive, and c is between 0...