You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: vl_alphanum.m
    path of file: ./repos/2015_Face_Detection/vlfeat/toolbox/misc
    
    the code of the file until where you have to start completion: function [strings, perm] = vl_alphanum(strings)
% VL_ALPHANUM  Sort strings using the Alphanum algorithm
%   STRINGS = VL_ALPHANUM(STRINGS) sorts the cell array of strings
%   STRINGS by using the Alphanum algorithm [1]. [STRINGS,PERM] =
%   VL_ALPHANUM(...) returns the corresponding permutation PERM as
%   well.
%
%   Example::
%     Alphanum sorts strings in a way that 'makes sense'. For instance
%
%      strings = {'B1', 'B2', 'B12', 'A12', 'A1', 'A2'} ;
%      sorted = vl_alphanum(strings) ;
%
%     produces the sorted array {'A1', 'A2', 'A12', 'B1', B2',
%     'B12'}. By contrast, SORT() produces the array {'A1', 'A12',
%     'A2', 'B1', B12', 'B2'} (note the position of the elements

    
function [strings, perm] = vl_alphanum(strings)
% VL_ALPHANUM  Sort strings using the Alphanum algorithm
%   STRINGS = VL_ALPHANUM(STRINGS) sorts the cell array of strings
%   STRINGS by using the Alphanum algorithm [1]. [STRINGS,PERM] =
%   VL_ALPHANUM(...) returns the corresponding permutation PERM as
%   well.
%
%   Example::
%     Alphanum sorts strings in a way that 'makes sense'. For instance
%
%      strings = {'B1', 'B2', 'B12', 'A12', 'A1', 'A2'} ;
%      sorted = vl_alphanum(strings) ;
%
%     produces the sorted array {'A1', 'A2', 'A12', 'B1', B2',
%     'B12'}. By contrast, SORT() produces the array {'A1', 'A12',
%     'A2', 'B1', B12', 'B2'} (note the position of the elements
%     'A12', 'B12').
%
%   References:
%   [1] Dave Koelle, 'The Alphanum Algorithm',
%   http://www.davekoelle.com/alphanum.html

chunks = regexp(strings, '(\d+|\D+)', 'tokens') ;
for i = 1:length(strings)
  chunks{i} = [chunks{i}{:}] ;
  for j = 1:length(chunks{i})
    if isstrprop(chunks{i}{j},'digit')
      chunks{i}{j} = sprintf('%020.0f',sscanf(chunks{i}{j},'%d')) ;
    end