This code is probably a little too tricky, however if I'm right, it just does what it needs to.

#! /usr/bin/perl

use 5.010;
use strict;
use warnings;
use File::Find;

my $dir = $ARGV[0] // q{.};

sub deepest {
  return if not -d;
  state $prev_dir = '';
  say if index $prev_dir, $_;
  $prev_dir = $_;
}

find(
  { wanted   => \&deepest,
    no_chdir => 1,
    bydepth  => 1,
  },
  $dir
);
[download]

The main idea behind this code is the following: if you traverse your directory structure in depth-first order, then you only need to check whether your current directory path is not a prefix (a slice starting at position 0) of the previous directory path. If it's not a prefix of the previous value, then print it.

To ease the understanding: your sample dir structure in depth-first order:

a/b/d/g/h
a/b/d/g/i
a/b/d/g # this is a prefix of the previous, so we don't want it
a/b/d
a/b/k # this is not a prefix of the previous, so we want it
a/b/c/e
a/b/c
a/b
a
[download]