Perl Weekly Challenge 020

Solutions to the first two tasks of the 20th Perl Weekly Challenge.

Challenge 020, Task #1

Split on Character Change

Write a script to accept a string from the command line and split it on change of character. For example, if the string is “ABBCDEEF”, then it should split like “A”, “BB”, “C”, “D”, “EE”, “F”.

My Code

say .comb(/(.)$0*/) for @*ARGS;

Challenge 020, Task #2

Amicable Numbers

Write a script to print the smallest pair of Amicable Numbers. For more information, please checkout this Wikipedia page.

My Code

sub divisors($_) { grep $_ %% *, (1, 2 ...^ * * 2 > $_) }

my @amicable-numbers = (1..^Inf).map: -> $a {
    my $b = $a.&divisors.sum;
    $a, $b if $a != $b && $b.&divisors.sum == $a;
}

sub MAIN(UInt $N = 1) {
    .say for @amicable-numbers[^$N];
}

The first pair is (220 284).