Add 332_Reconstruct_Itinerary.java

Author: seanprashad

Graphs/332_Reconstruct_Itinerary.java

@@ -0,0 +1,29 @@
+class Solution {
+    public List<String> findItinerary(List<List<String>> tickets) {
+        if (tickets == null || tickets.size() == 0) {
+            return Collections.emptyList();
+        }
+
+        LinkedList<String> result = new LinkedList<>();
+        Map<String, PriorityQueue<String>> graph = new HashMap<>();
+
+        for (List<String> t : tickets) {
+            graph.putIfAbsent(t.get(0), new PriorityQueue<>());
+            graph.get(t.get(0)).add(t.get(1));
+        }
+
+        dfs("JFK", graph, result);
+
+        return result;
+    }
+
+    private void dfs(String departure, Map<String, PriorityQueue<String>> graph, LinkedList<String> path) {
+        PriorityQueue<String> arrivals = graph.get(departure);
+
+        while (arrivals != null && !arrivals.isEmpty()) {
+            dfs(arrivals.poll(), graph, path);
+        }
+
+        path.addFirst(departure);
+    }
+}