Perl Weekly Challenge 020

ch-1.pl

use strict;
use warnings;
##
# Write a script to accept a string from command line and split it on change of character.
##
my $string = $ARGV[0];
my @letters = split(//, $string);
my $letter;
my $letter_previous = shift @letters;
do{ 
    $letter = shift @letters;
    print $letter_previous if($letter eq $letter_previous); 
    print "$letter_previous\n" if($letter ne $letter_previous); 
    $letter_previous = $letter; 
}while(@letters);
print $letter_previous if($letter eq $letter_previous); 
print "$letter_previous\n" if($letter ne $letter_previous);
print "\n";  

ch-1.rk

##
# Write a script to accept a string from command line and split it on change of character.
##
my $string = @*ARGS[0];
my @letters = split(/""/, $string);
my $letter;
@letters.shift();
my $letter_previous = @letters.shift();
repeat {
    $letter = @letters.shift();
    print $letter_previous if ($letter eq $letter_previous);
    print "$letter_previous\n" if ($letter ne $letter_previous);
    $letter_previous = $letter;
}while (@letters);
print $letter_previous if ($letter eq $letter_previous);
print "$letter_previous\n" if ($letter ne $letter_previous);

ch-2.pl

use strict;
use warnings;
##
# Write a script to print the smallest pair of Amicable Numbers.
##
use boolean; 
use Thread;
use constant RANGE_SIZE => 50; 
use constant THREAD_COUNT => 4;  

sub factor_sum{ 
    my(@numbers) = @_;
    my %number_sof; 
    foreach my $n (@numbers){  
        my @factors = (1);
            foreach my $j (2..sqrt($n)){
            push @factors, $j if $n % $j == 0;
            push @factors, ($n / $j) if $n % $j == 0 && $j ** 2 != $n;
        }    
        $number_sof{$n}=unpack("%32C*", pack("C*", @factors));  
    } 
    return \%number_sof;   
}

MAIN:{
    my %number_sof; 
    my @threads;
    my $range_start = 1;
    my $range_end = RANGE_SIZE; 
    my $found = false; 
    do{
        for(0 .. (THREAD_COUNT - 1)){
            my $t = Thread->new(\&factor_sum, ($range_start .. $range_end)); 
            push @threads, $t;  
            $range_start = $range_end + 1;
            $range_end = $range_start + RANGE_SIZE;  
        }  
        foreach my $t (@threads){
            my $sof = $t->join();
            @number_sof{keys %{$sof}} = values %{$sof};  
            foreach my $k (values %{$sof}){
                if($number_sof{$k}){
                    if($number_sof{$number_sof{$k}} && 
                       $number_sof{$number_sof{$k}} == $k && 
                       $number_sof{$k} != $k && !$found){
                           print "First amicable pair of numbers: $k " . $number_sof{$k} . " \n"; 
                           $found = true;   
                    }    
                }  
            }     
        }  
        @threads = (); 
    }while(!$found);     
}

ch-2.rk

##
# Write a script to print the smallest pair of Amicable Numbers.
##
constant RANGE_SIZE = 50; 
sub factor-sum(@numbers){
    my %number_sof;
    for @numbers -> $n {
        my @factors = (1);
        for (2 .. sqrt($n)) -> $j {
            @factors.push($j) if $n %% $j;
            @factors.push($n / $j) if $n %% $j && $j ** 2 != $n;
        }
        my $sum = [+] @factors;  
        %number_sof{$n} = $sum; 
    }
    return %number_sof;
}  
my $range_start = 1;
my $range_end = RANGE_SIZE; 
my $found = Bool::False;
my %number_sof; 
my @promises;
while (!$found) {
    @promises = ();
    for (0 .. 3) {
        @promises.push(Promise.start( {
            factor-sum($range_start .. $range_end);  
        }));      
        $range_start = $range_end + 1;
        $range_end = $range_start + RANGE_SIZE;
    }  
    await(|@promises);  
    for @promises -> $p {
        %number_sof{ keys $p.result} = values $p.result;
        for (values $p.result) -> $k {
            if (%number_sof{$k}) {
                    if (%number_sof{%number_sof{$k}} &&
                       %number_sof{%number_sof{$k}} == $k &&
                       %number_sof{$k} != $k && !$found) {
                           say "First amicable pair of numbers: $k " ~ %number_sof{$k};
                           $found = Bool::True;
                    }
            }
        } 
    }  
}