
Sorting Algorithm

This is a sorting algorithm.   It may be applied to a set of data in order to sort it.    
For comparing various sorts, see compare sorts.  
For other sorting algorithms,   see sorting algorithms,   or:

O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort


Task

Sort an array (or list) of strings in order of descending length, and in ascending lexicographic order for strings of equal length.

Use a sorting facility provided by the language/library, combined with your own callback comparison function.


Note:   Lexicographic order is case-insensitive.




module sorts_with_custom_comparator
  implicit none
contains
  subroutine a_sort(a, cc)
    character(len=*), dimension(:), intent(inout) :: a
    interface
       integer function cc(a, b)
         character(len=*), intent(in) :: a, b
       end function cc
    end interface
 
    integer :: i, j, increment
    character(len=max(len(a), 10)) :: temp
 
    increment = size(a) / 2
    do while ( increment > 0 )
       do i = increment+1, size(a)
          j = i
          temp = a(i)
          do while ( j >= increment+1 .and. cc(a(j-increment), temp) > 0)
             a(j) = a(j-increment)
             j = j - increment
          end do
          a(j) = temp
       end do
       if ( increment == 2 ) then
          increment = 1
       else
          increment = increment * 5 / 11
       end if
    end do
  end subroutine a_sort
end module sorts_with_custom_comparator