Dear Community,
I have to align several arrays into a 2D matrix. Let's say, I have the two vectors :

['A','B','C'],
['A','B','D']
[download]

The output should look like:

A  A
B  B
C
   D
[download]

In order to achieve that "simple" version, I wrote the script which I attach below. It takes the first array and aligns the second and takes the second and aligns the first and outputs the version with the minimum amount of holes.
If, however, there are the following three vectors:

['A','B','C'],
['A','D','C'],
['A','B','C']
[download]

The script outputs (6 holes):

A       A       A
B       B
C       C
                D
                C
[download]

An "intelligent" person would find instead: (3holes)

A       A       A
B       B
                D
C       C       C
[download]

I wonder if there is a way to achieve that. Actually, I'd need a code that "looks forward" which rows come and align either the right or the left side ... mhm.
Thanks for ideas/solutions,
Jan
script:

#!/usr/bin/perl -w

use strict;
#use Data::Dumper;

my $hash;
#$hash->{'Vector1'} = ['A','B','D','H','J'];
#$hash->{'Vector2'} = ['A','B','C','D'];
#$hash->{'Vector4'} = ['H','K'];

$hash->{'Vector3'} = ['A','B','C'];
$hash->{'Vector4'} = ['A','D','C'];
$hash->{'Vector5'} = ['A','B','C'];



#print Dumper($hash);

my $count_total = scalar (keys %{$hash});
my @keys = keys %{$hash};
my $aligned;
my $minimum;

my $key_count=0;
for (0 .. $#keys) {
  my $test = shift(@keys);
  push(@keys,$test);

  #
  # push first into results matrix
  # to start with
  #

  my @result;
  foreach (@{$hash->{$keys[0]}}) {
    push(@result,[$_]);
  }

  #
  # compare
  #

  my $count_processed=0;
  my @vector;
  foreach (keys %{$hash}) {
    if (($count_processed+2)>$count_total) {
      last;
    }
    @vector = @{$hash->{$keys[$count_processed+1]}};
    my $i=0;
    while ($i <= $#vector) {
      my $entry = $vector[$i];
      if (defined(${$result[$i]}[0])) {
    # print "1)Is ";
    # print $entry;
    # print " in ";
    # print join(',',@{$result[$i]});
    # print " ?";
    if (grep $_ eq $entry,@{$result[$i]}) {
      #   print " => yes\n";
      push(@{$result[$i]},$entry);
    } else {
      #   print " => no\n";
      splice(@vector,$i,0,'');
      my @space;
      for (0 .. ($count_processed-$#{$result[$i]})) {
        push(@space,'');
      }
      push(@{$result[$i]},@space);
    }
    ;
      } else {
    # print "undefined => shift\n";
    my @space;
    for (0 .. $count_processed) {
      push(@space,'');
    }
    push(@{$result[$i]},@space,$entry);
      }
      $i++;
    }

    #
    # the latest column might have missing ''s at the end. This needs 
+to be
    # filled up
    #

    my $p=0;
    foreach (@result) {
      if ($#{$result[$p]} < $#{$result[0]} ) {
    push(@{$result[$p]},'');
      }
      $p++;
    }
    $count_processed++;
  }

  #
  # count the number of holes
  #

  my $n=0;
  foreach (@result) {
    foreach (@$_) {
      # print "$_ \t";
      if ($_ eq '') {
    $n++;
      }
    }
  }
#  print "\n";
 
  if($key_count == 0){
    $minimum = $n;
    $aligned = {
        'matrix' => [@result],
        'n'      => $n
           };
  }else{
    if($n < $minimum){
      $minimum = $n;
      $aligned = {
          'matrix' => [@result],
          'n'      => $n
         };

    }
  }
  $key_count++;
}
  
print "minimal configuration ($aligned->{'n'} holes):\n";
foreach (@{$aligned->{'matrix'}}) {
  foreach (@$_) {
    print "$_ \t";
  }
  print "\n";
}
[download]

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