update 3637 mod solution

java/search/BinarySearch3637.java

@@ -69,9 +69,9 @@ public class BinarySearch3637 {
         int mid = low + (high - low) / 2;
 
         if (a.get(mid) >= x) {
-            rightBoundRecursive(x, a, mid + 1, high);
+            return rightBoundRecursive(x, a, mid + 1, high);
         } else {
-            rightBoundRecursive(x, a, low, mid - 1);
+            return rightBoundRecursive(x, a, low, mid - 1);
         }
     }
 }