use strict;
use warnings;

my %A;
my ($max_row, $max_col) = (4,4);

# autovivify interesting rows/cols of %A
while (<DATA>) {
  warn("Line $.: cannot understand: $_") , next unless /A(\d+);A(\d+)/;
  my ($row, $col) = ($1,$2);
  $A{$row}{$col}++;
  $A{$col}{$row}++; # uncomment if relationship is not bidirectional
}

# print col. header
print "    ";
printf("A%-3d",$_) for (1..$max_col);
print "\n";

#print matrix A
for my $row (1 .. $max_row) {
  printf("A%-3d", $row);

  for my $col (1 .. $max_col) {
    printf(" %-3d",  exists $A{$row}{$col} ? "1" : "0" );
  }
  print "\n";
}


__DATA__
A1;A4
A2;A3
A2;A4
A1;A3