sub lc_substr {
  my ($s, $t) = @_; 
  my $z = 0;
 
  my @S = (undef, split(/ /, $s));
  my @T = (undef, split(/ /, $t));
  
  my $m = scalar @S; 
  my $n = scalar @T; 

  my @LCS = ();
  my @start = ();
  my @end = ();
 
  for my $i ( 1 .. $m ) { 
    for my $j ( 1 .. $n ) {
      if ($S[$i] =~ m/^$T[$j]$/ig && $S[$i] ne undef && $T[$j] ne undef &&$S[$i] ne " "&&$T[$j] ne " ") {
        $L[$i-1][$j-1] ||= 0;  
        $L[$i][$j] = $L[$i-1][$j-1] + 1;
        if ($L[$i][$j] > $z) {
          $z = $L[$i][$j];
          @ret = (); 
		  @start = ();
		  @end = ();
		  @prod = ();
        }
        if ($L[$i][$j] == $z) {
		  $start = $i-$z+1;
		  $end = $i;
          push(@start,$start);
		  push(@end,$end);
		  push(@prod,$t);
        }
      }
    }
  }  
  
   $num = scalar @start;
   for ($n = 0; $n < $num;$n++){
      if($prod[$n] ne ""){
         $str = $prod[$n]." "."[".$start[$n].",".$end[$n]."]";
	     push (@LCS, $str);
	  }
   }   
   return @LCS;  
}