Conditional Sentences: Talking about what didn't happen

If there were more apartments, the rent would be cheaper. 

You might have stayed dry if you'd brought an umbrella.

Which situation does this conditional describe?
"We wouldn't have gone for a picnic if we'd looked at the weather forecast."

We didn't look at the weather forecast and we went for a picnic

We looked at the weather forecast and we didn't go for a picnic 

We didn't look at the weather forecast and we didn't go for a picnic

If he had known how much it would cost, he wouldn't have said he would pay.

If she had been here on time, we might not have been late for the party.

Had you thought of me, you would have bought me flowers. 

If you had thought of me, you would bought me flowers.

Why is "had you thought of me, you would have bought me flowers" not an incorrect sentence?

Because it's a special version of a conditional using something called inversion

Which one of these conditionals is not about the past?

If they'd gotten good ratings, they would have continued making the show.

I would have went if I'd known how to get there. 

Which one is about the past?