Phew. Truth and justice has prevailed.
We explained to the coordinator that our code was only vaguely similar because we prepared our programs in the pre-planning stages together. Any other similarities were coincidental.
So, to test our skills, the coordinator had us each write the method again - from scratch - on paper. We both did. We both did it right (although I realized a mistake I had made upon the initial submission of the code).
And - in the end - it all worked out.
A happy ending.
Let this be a lesson to all of you. Sometimes, even NOT cheating isn’t good enough. You have to do some sort of super NOT cheating that even an all-powerful deity could not perceive.