Air Carrier pilot reported the push back crew did not follow procedures and pushed them into another parked aircraft.

Narrative

Received pushback clearance from ZZZ gate XX. After pushback; we were unsure if we had adequate room to maneuver out of alley. We asked pushback crew if this was the normal drop point for the gate. The crew did not know. After discussion; we wanted to be pushed back more for an additional safety margin (we were close to a B777). This was followed by a big jolt. A push crew should be trained how far back to push a jet relative to each gate to provide a safe exit point for the departing jet. And a push should never start without confirming with Caption and brake light off on nose gear. Also It was dark.In discussion with ZZZ personnel it was mentioned that ZZZ operations has hired X number of new personnel (was this an exaggeration) since the beginning of the year. It was insinuated that with all the new hires and high turnover that perhaps there are many inexperienced personnel in safety critical positions. I am always a big believer in middle management being responsible and intimately involved in training to the very highest standards.