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|
#!/usr/bin/perl
use strict;
use warnings;
my $S = $ARGV[0] || "25525511135";
my @V = ipv4_partition($S);
print sprintf("%s = %s\n", $S, join (", ", @V));
sub ipv4_partition {
my ($ipv4_string) = @_;
my @valid = ();
my $ipv4 = '';
foreach my $i (1 .. length($ipv4_string)-3) {
foreach my $j ($i+1 .. length($ipv4_string)-2) {
foreach my $k ($j+1 .. length($ipv4_string)-1) {
$ipv4 = substr($ipv4, 0, $k) . "." . substr($ipv4, $k)
if (length($ipv4) >= $k);
$ipv4 = substr($ipv4, 0, $j) . "." . substr($ipv4, $j)
if (length($ipv4) >= $j);
$ipv4 = substr($ipv4, 0, $i) . "." . substr($ipv4, $i)
if (length($ipv4) >= $i);
push @valid, $ipv4 if is_valid($ipv4);
$ipv4 = $ipv4_string;
}
}
}
return @valid;
}
sub is_valid {
my ($ipv4) = @_;
return 0 if (length($ipv4) == 0);
foreach my $octet (split /\./, $ipv4) {
return 0 if ((length($octet) > 3)
||
($octet > 255)
||
(length($octet) > 1 && $octet =~ /^0/));
}
return 1;
}
|
