rearrange

  Write a static method rearrange that takes an
    array of integers as an argument and that rearranges the values so that all
    of the multiples of 3 come first followed by numbers that are one greater
    than a multiple of 3 followed by numbers that are two greater than a
    multiple of 3.  For example, if a variable called "list" stores this
    sequence of values:

	(23, 12, 8, 0, 4, 80, 9, 7, 30, 99, 50, 42, 13, 47, 2, 16, 87, 75)

    Then the following call:

	rearrange(list);

    Should rearrange the values to look something like this:

	(12, 0, 9, 30, 99, 42, 87, 75, 4, 13, 16, 7, 23, 47, 2, 50, 8, 80)
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~  ~~~~~~~~~~~~  ~~~~~~~~~~~~~~~~~~~~
                multiples of 3        1 more than a     2 more than a
                                      multiple of 3     multiple of 3
 
    This is only one possible arrangement.  Any arrangement that puts the
    multiples of 3 first followed by the values that are one more than a
    multiple of 3 followed by the values that are two more than a multiple of 3
    is acceptable.  You are not allowed to use an auxiliary data structure such
    as a temporary array or ArrayList to solve this problem.  You may assume
    that all values in the array are greater than or equal to 0.

    Write your solution to rearrange below.