64 lines
1.5 KiB
Perl
64 lines
1.5 KiB
Perl
|
package BinaryGap;
|
||
|
|
use Modern::Perl;
|
||
|
|
# use List::MoreUtils qw(first_index); # codility does not have
|
||
|
|
use List::Util qw(max first);
|
||
|
|
|
||
|
|
use Data::Dumper;
|
||
|
|
|
||
|
|
|
||
|
|
sub solution {
|
||
|
|
# N is an integer within the range [1..2,147,483,647]
|
||
|
|
my ($N) = @_;
|
||
|
|
my $max_gap = 0;
|
||
|
|
# Make sure number is in acceptable range, if not return 0
|
||
|
|
if (($N < 1) || ($N > '2147483647')) {
|
||
|
|
return $max_gap;
|
||
|
|
}
|
||
|
|
# convert integer to binary
|
||
|
|
my $bin_num = unpack("B*", pack("N", $N));
|
||
|
|
|
||
|
|
# convert to array
|
||
|
|
my @bin_array = split('',$bin_num);
|
||
|
|
|
||
|
|
# find first 1. If there is not one, return for performance
|
||
|
|
my $first_index;
|
||
|
|
for (0 .. $#bin_array) {
|
||
|
|
if ($bin_array[$_] == 1) {
|
||
|
|
$first_index = $_;
|
||
|
|
last;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return $max_gap unless $first_index;
|
||
|
|
|
||
|
|
# If there are less than two 1s in the array, return 0
|
||
|
|
my $ones_total_count = grep { $_ == 1 } @bin_array;
|
||
|
|
if ($ones_total_count < 2) {
|
||
|
|
return $max_gap;
|
||
|
|
}
|
||
|
|
|
||
|
|
# If there is just one 0 in the array, return 0
|
||
|
|
my $zeros_total_count = grep { $_ == 0 } @bin_array;
|
||
|
|
if ($zeros_total_count < 2) {
|
||
|
|
return $max_gap;
|
||
|
|
}
|
||
|
|
|
||
|
|
# Get all 1 indexes
|
||
|
|
my @i = grep { $bin_array[$_] == 1 } 0 .. $#bin_array;
|
||
|
|
my $last_index = $i[$#i];
|
||
|
|
|
||
|
|
my $zero_count = 0;
|
||
|
|
for my $index ($first_index .. $last_index) {
|
||
|
|
my $num = $bin_array[$index];
|
||
|
|
if ($num == 1) {
|
||
|
|
$zero_count = 0;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
$zero_count++;
|
||
|
|
$max_gap = max($zero_count, $max_gap);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return $max_gap;
|
||
|
|
}
|
||
|
|
|
||
|
|
1;
|