You start with 11 top tricks and have a wonderful chance of establishing a diamond (if they divide 4–3) for your 12th trick. If that doesn’t pan out, there is always the heart suit.
Ruff the ♣K, (assuming 4–3 diamonds, you need the entry to set up the suit), cash the ♦A discarding a heart, and ruff a diamond high. Assuming both follow, cross to the ♠Q and ruff a second diamond. If both follow, diamonds have divided 4–3, so you can draw trumps, cross to a high heart, ruff a diamond and back to a second high heart to discard your remaining heart on an established diamond. No need to deal with the ♥Q when diamonds are 4–3.
A more challenging scenario develops when East turns up with five diamonds precluding diamond establishment. Now your best move is to reduce to this five-card end position, not having touched hearts:
At this point, you should have a very good idea of East’s remaining five cards: After all, you know that two of them are diamonds. You have a count on spades and assuming clubs are 7–3, you have a count on the hand.
If East has three hearts remaining — any three hearts — play a spade and discard the ♥J. If East discards a diamond, you have the entries to set up a diamond winner. If East discards a heart, your third heart is high after you cash the ♥A K and ruff a diamond to get back to your hand.
If East has two hearts and has not discarded any (meaning he started with a 3=2=5=3 pattern), take the heart finesse.
Finally, if East started with six diamonds, there is no need to ruff any more diamonds; just reduce to the same end position, again having a count on East’s heart length. Anytime the count tells you that East started with one heart (3=1=6=3 or 4=1=6=2), cross to the ♥A, ruff a diamond and take the heart finesse.