First is the fastest among all...Because it uses one bitwise and one arithmatic operator..
Next comes the second. 2 bitwise and two arithmatic operator.
The code with highest time complexity is third. Once my teacher taught " It looks like simple, but When ever a multiplication code is called the compiler will perform inner addition operation. But due to its coding structure, most programmers use this kind of notations.".
Hope this helps you...
Have a happy coding...:D