cs: add “338. Counting Bits”

Signed-off-by: Matej Focko <mfocko@redhat.com>

cs/counting-bits.cs

@@ -0,0 +1,11 @@
+public class Solution {
+    public int[] CountBits(int n) {
+        var counters = new int[n + 1];
+
+        for (var i = 1; i <= n; ++i) {
+            counters[i] = counters[i >> 1] + i % 2;
+        }
+
+        return counters;
+    }
+}