private static bool isValidMove(Coin[,] state, Move m)
{
return
isUsefulMove(state, m.Cell, m.DestinationCell()) ||
isUsefulMove(state, m.DestinationCell(), m.Cell)
;
}
private static Coin[,] exchange(Coin[,] state, Move move)
{
Coin[,] result = Clone(state);
result.put(move.DestinationCell(), state.get(move.Cell));
result.put(move.Cell, state.get(move.DestinationCell()));
return result;
}