added comments

Author: Ram swaroop

src/me/ramswaroop/bits/CountSetBits.java

@@ -31,13 +31,19 @@ static int countSetBits(int number) {
     /**
      * Optimized version.
      *
+     * Uses BRIAN KERNIGAN'S bit counting. Acc. to this, the  right most/least significant set bit is unset
+     * in each iteration. The time complexity is proportional to the number of bits set.
+     *
+     * {@see http://stackoverflow.com/questions/12380478/bits-counting-algorithm-brian-kernighan-in-an-integer-time-complexity}
+     * {@see http://graphics.stanford.edu/~seander/bithacks.html#ParityNaive}
+     *
      * @param n
      * @return
      */
     static int countSetBits(long n) {
         int count = 0;
         while (n > 0) {
-            n &= n - 1;
+            n &= n - 1; // right most set bit in n is unset
             count++;
         }
         return count;

src/me/ramswaroop/bits/Multiply.java

@@ -7,6 +7,13 @@
  * @date: 6/3/15
  * @time: 11:35 PM
  */
+
+/**
+ * Time Complexity: O(1)
+ * Space Complexity: O(1)
+ * <p/>
+ * Note: Works only for positive integers.
+ */
 public class Multiply {
 
     /**

src/me/ramswaroop/bits/Parity.java

@@ -17,8 +17,9 @@
 public class Parity {
 
     /**
-     * Uses BRIAN KERNIGAN'S bit counting. The time complexity is
-     * proportional to the number of bits set.
+     * Uses BRIAN KERNIGAN'S bit counting. Acc. to this, the  right most/least significant set bit is unset
+     * in each iteration. The time complexity is proportional to the number of bits set.
+     *
      * {@see http://stackoverflow.com/questions/12380478/bits-counting-algorithm-brian-kernighan-in-an-integer-time-complexity}
      * {@see http://graphics.stanford.edu/~seander/bithacks.html#ParityNaive}
      *