Given a list of airline tickets represented by pairs of departure and arrival airports [from, to], reconstruct the itinerary in order. All of the tickets belong to a man who departs from JFK. Thus, the itinerary must begin with JFK.
Note:
<li>If there are multiple valid itineraries, you should return the itinerary that has the smallest lexical order when read as a single string. For example, the itinerary <code>["JFK", "LGA"]</code> has a smaller lexical order than <code>["JFK", "LGB"]</code>.</li>
<li>All airports are represented by three capital letters (IATA code).</li>
<li>You may assume all tickets form at least one valid itinerary.</li>
Example 1:
Input:[["MUC", "LHR"], ["JFK", "MUC"], ["SFO", "SJC"], ["LHR", "SFO"]]Output:["JFK", "MUC", "LHR", "SFO", "SJC"]
Example 2:
Input:[["JFK","SFO"],["JFK","ATL"],["SFO","ATL"],["ATL","JFK"],["ATL","SFO"]]Output:["JFK","ATL","JFK","SFO","ATL","SFO"]Explanation: Another possible reconstruction is["JFK","SFO","ATL","JFK","ATL","SFO"]. But it is larger in lexical order.