Add all the A tasks

Task/Averages-Median/Java/averages-median-2.java

@@ -0,0 +1,10 @@
+public static double median2(List<Double> list){
+   PriorityQueue<Double> pq = new PriorityQueue<Double>(list);
+   int n = list.size();
+   for (int i = 0; i < (n-1)/2; i++)
+      pq.poll(); // discard first half
+   if (n % 2 != 0) // odd length
+      return pq.poll();
+   else
+      return (pq.poll() + pq.poll()) / 2.0;
+}