I have read English grammar lesson about "Third Conditional" and got confused. Let's consider the following two sentences:
If I would have bought the house, I would have got a mortgage.
If I had bought the house, I would have got a mortgage.
Pattern which has been used to make the first sentence is considered to be wrong, meanwhile the second one is considered as a correct one. So why in the first half of the sentence it is incorrect to use would, meanwhile in the other half it is OK to use it?
Also is there a general pattern for construction of "Third Conditional" sentences?