Reachability with Flight Schedules (Time-Feasible Path)

Problem: Flight Reachability with Schedule Constraints You are given a list of flights flights. Each flight contains: origin: departure airport (string) destination: arrival airport (string) departure_time: departure time (integer or comparable timestamp) arrival_time: arrival time (integer or comparable timestamp) You are also given a start airport start and an end airport end. Determine whether there exists an itinerary from start to end (using one or multiple flights) such that: The first flight departs from start and the last flight arrives at end. For a connection, the next flight’s departure time must be not earlier than the previous flight’s arrival time (i.e., the itinerary must be time-feasible). Return true if such an itinerary exists; otherwise return false. I/O Format (assumption for implementation) Input: Line 1: integer n (number of flights) Next n lines: origin destination departure_time arrival_time Last line: start end Output: one line true or false Constraints 1 <= n <= 2 * 10^5 Airport codes are non-empty strings Times are non-negative integers and comparable Examples Input: 3 SFO LAX 1 2 LAX JFK 3 5 SFO JFK 10 12 SFO JFK Output: true Input: 2 SFO LAX 5 7 LAX JFK 6 9 SFO JFK Output: false Input: 4 A B 1 3 B C 3 4 C D 4 6 A D Output: true Input: 1 A B 1 2 A C Output: false Input: 3 A B 1 2 B A 2 3 A C 3 4 A C Output: true Example Input 3 SFO LAX 1 2 LAX JFK 3 5 SFO JFK 10 12 SFO JFK Output true