Temperature and Humidity Matching

Given two lists sorted by time, temperature and humidity. Temperature entries have the format (time, city, reading), and humidity entries have the format (time, city, reading). Match each temperature reading with the most recent humidity reading from the same city. Example Input [[(1, 'NYC', 12), (5, 'SFO', 20)], [(0, 'SFO', 12), (6, 'NYC', 2)]]