1 files changed, 41 insertions, 0 deletions
diff --git a/challenge-258/bruce-gray/java/ch-2.java b/challenge-258/bruce-gray/java/ch-2.java
new file mode 100644
index 0000000000..f7f9036d89
--- /dev/null
+++ b/challenge-258/bruce-gray/java/ch-2.java
@@ -0,0 +1,41 @@
+// java java/ch-2.java
+import java.util.List;
+import java.util.stream.IntStream;
+import java.util.stream.Collectors;
+public class ch_2 {
+
+
+    static int task2 ( Integer k, List<Integer> ns ) {
+        Integer[] ints = ns.toArray(new Integer[0]);
+
+        return IntStream.range(0, ints.length)
+            .filter(i -> Integer.bitCount(i) == k)
+            .mapToObj(i -> ints[i])
+            .collect(Collectors.summingInt(Integer::intValue));
+    }
+
+
+
+    // Test harness
+    static int test_number = 1;
+    static void  plan ( Integer count ) { System.out.printf("1..%d\n", count); }
+    static boolean is ( Integer got, Integer expected, String desc ) {
+        boolean ret = got == expected;
+        System.out.printf("%s %d - %s\n", (ret ? "ok" : "not ok"), test_number++, desc);
+        return ret;
+    }
+    public static void main(String[] args) {
+        record Testcase ( Integer expected, Integer in_k, List<Integer> in_nums ) {}
+
+        List<Testcase> tst = List.of(
+            new Testcase( 17, 1, List.of(2, 5, 9, 11, 3) ),
+            new Testcase( 11, 2, List.of(2, 5, 9, 11, 3) ),
+            new Testcase(  2, 0, List.of(2, 5, 9, 11, 3) )
+        );
+        plan(tst.size());
+        for (Testcase t : tst) {
+            is( task2(t.in_k, t.in_nums), t.expected, "k=" + t.in_k);
+        }
+
+    }
+}