use warnings;
use strict;
use Inline::Files;

#open(AB, "try_fimo.txt")  || die("cannot open");
#my @data = <AB>;
#close(AB);
#chomp(@data);
#
#open(BC, "try_fimo2.txt") || die("cannot open");
#my @data2 = <BC>;
#close(BC);
#chomp(@data2);

my @data = <AB>;
my @data2 = <BC>;

my ($t1, $t2, $t3);
my (@tf1, @seq1, @dis1);
my (@tf2, @seq2, @dis2);
my (@tf3, @seq3, @dis3);

foreach my $line (@data) {
  foreach my $line2 (@data2) {
    if ($line2 =~ /(.*?)\s+(.*?)\s+(.*)/) {
      $t1 = $1; # eg. in first row from file2 i.e. ABC, it will first take A followed by B & C 
      $t2 = $2;
      $t3 = $3;
    }

    if ($line =~ /(.*?)\s+(.*?)\s+(.*)/) {
      if ($1 eq $t1) {
        push(@tf1,  $1);
        push(@seq1, $2);
        push(@dis1, $3);
        # print $1,"\t",$2,"\t",$3,"\t";
      } elsif ($1 eq $t2) {
        push(@tf2,  $1);
        push(@seq2, $2);
        push(@dis2, $3);
      } elsif ($1 eq $t3) {
        push(@tf3,  $1);
        push(@seq3, $2);
        push(@dis3, $3);       
			}
    }      
  }
}

for (my $i = 0; $i < @tf1; $i++) {
  for (my $j = 0; $j < @tf2; $j++) {
    for (my $k = 0; $k < @tf3; $k++) {
      if (($seq1[$i] eq $seq2[$j]) && ($seq1[$i] eq $seq3[$k])) {
        if (($tf1[$i] ne $tf2[$j]) && ($tf1[$i] ne $tf3[$k])) {
          print $tf1[$i],  "\t",
                $seq1[$i], "\t",
                $dis1[$i], "\t",
                $tf2[$j],  "\t",
                $seq2[$j], "\t",
                $dis2[$j], "\t",
                $tf3[$k],  "\t",
                $seq3[$k], "\t",
                $dis3[$k], "\n";
        }
      }
    }
  }
}

__AB__
A seq1 20
B seq2 25
B seq2 80
B seq1 40
C seq1 25
D seq2 30
E seq2 45

__BC__
A B C