A type of long-term memory where I can remember full dialogues
the cognitive skills of a human population have a great variance. I am more like your friend, with episodic memory below average but semantic memory above average. You seem to have episodic memory above average (I envy you on that, because a large part of our feeling of self identity depends on episodic memory). There are extreme cases of people that remember almost everything they experience or read, or hear. A nice book on the topic is Luria's book "the mind of a mnemonist". It is a short book, and I'm sure you'll find it pretty interesting.