I don't know what algorithms there are for doing N-way diffs, but this came up with something sane for your example: 

use strict;
use warnings;

use Algorithm::Diff qw( );

my @seqs = (
   [qw( A B C )],
   [qw( A D C )],
   [qw( A B C )],
);

my @combined;
my @grid;

for my $col_idx (0..$#seqs) {
   my $seq = $seqs[$col_idx];

   my $diff = Algorithm::Diff->new(\@combined, $seq);

   my @new_combined;
   my @new_grid;
   while ($diff->Next()) {
      if ($diff->Same()) {
         for ($diff->Range(1)) {
            push @new_combined, $combined[$_];
            push @new_grid,     $grid[$_];

            $new_grid[-1][$col_idx] = 1;
         }
      } else {
         for ($diff->Range(1)) {
            push @new_combined, $combined[$_];
            push @new_grid,     $grid[$_];
         }

         for ($diff->Range(2)) {
            push @new_combined, $seq->[$_];
            push @new_grid,     [];

            $new_grid[-1][$col_idx] = 1;
         }
      }
   }

   @combined = @new_combined;
   @grid     = @new_grid;
}

for my $row_idx (0..$#combined) {
   my $ch = $combined[$row_idx];

   for my $col_idx (0..$#seqs) {
      print($grid[$row_idx][$col_idx] ? $ch : " ", " ");
   }

   print("\n");
}

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

[download]

In reply to Re: Converting Arrays into Matrix by ikegami
in thread Converting Arrays into Matrix by janDD

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.