Reconstruct Itinerary

You are given a list of airline tickets where tickets[i] = [fromi, toi] represent the departure and the arrival airports of one flight. Reconstruct the itinerary in order and return it. Examples Example 1: Input: tickets = [["MUC","LHR"],["JFK","MUC"],["SFO","SJC"],["LHR","SFO"]] Output: ["JFK","MUC","LHR","SFO","SJC"] Example 2: Input: tickets = [["JFK","SFO"],["JFK","ATL"],["SFO","ATL"],["ATL","JFK"],["ATL","SFO"]] Output: ["JFK","ATL","JFK","SFO","ATL","SFO"] Explanation: The itinerary ["JFK","ATL","JFK","SFO","ATL","SFO"] has a smaller lexical order than ["JFK","SFO","ATL","JFK","ATL","SFO"]. Constraints 1 <= tickets.length <= 300 tickets[i].length == 2 from_i.length == 3 to_i.length == 3 from_i and to_i consist of uppercase English letters. from_i != to_i