java: add «2558. Take Gifts From the Richest Pile»

URL:	https://leetcode.com/problems/take-gifts-from-the-richest-pile/
Signed-off-by: Matej Focko <me@mfocko.xyz>

java/take-gifts-from-the-richest-pile.java

@@ -0,0 +1,19 @@
+class Solution {
+  public long pickGifts(int[] gifts, int k) {
+    var q = new PriorityQueue<Integer>(Comparator.reverseOrder());
+    for (var gift : gifts) {
+      q.offer(gift);
+    }
+
+    for (int i = 0; i < k; ++i) {
+      int richest = q.poll();
+      q.offer((int) Math.sqrt(richest));
+    }
+
+    long remaining = 0;
+    while (!q.isEmpty()) {
+      remaining += q.poll();
+    }
+    return remaining;
+  }
+}