Perl Weekly Challenge 131: no coffee, no elegance

One way to let me improve my knowledge about Raku (aka Perl 6) is to implement programs in it. Unluckily, I don’t have any production code to implement in Raku yet (sob!). So, why not try solving the Perl Weekly Challenge tasks?

In the following, the assigned tasks for Challenge 110.

PWC 131 - Task 1

The first task was about splitting an incoming set of ordered integers into array, so that each array contains consecutive values.
I decided to use an array @results that acts as an array of arrays where each embedded array is one of the resulting arrays required by the task. It is quite clear that the first array in @results is the first element in the list of input integers.
Then it does suffice to iterate over the array of integers (skipping the first element) and see if the last element of the last sub-array has a distance of 1 from the current value. If the distance is 1 the value is pushed into the very last array in the @results, otherwise it means a new sub array must be created with the starting element as the current one.
The code therefore looks like:

sub MAIN( *@values where { @values.elems > 1 && @values.grep( * ~~ Int ).elems == @values.elems } ) {
    my @results;
    @results.push: [ @values[ 0 ] ];
    for 1 ..^ @values.elems {
        if @results[ * - 1 ][ * - 1 ] - @values[ $_ ] == -1 {
            @results[ * - 1 ].push: @values[ $_ ];
        }
        else {
            @results.push: [ @values[ $_ ] ];
        }
    }

    @results.say;
}


The only trick, thus, is to use the last to last element as [ * - 1 ][ * - 1 ].

PWC 131 - Task 2

The second task was about recognizing how many starting delimiters and closing delimiters, passed as input, are there in another input string.
Assuming therefore that the $delimiters input string is made by pairs, it is quite easy to iterate over the pairs and match the $needle searching for string. The results are pushed into two different arrays, that are then printed on separated lines:

sub MAIN( Str $delimiters where { $delimiters.chars %% 2 },
          Str $needle where { $needle.chars >= 2 } ) {
    my Str @openings;
    my Str @closings;

    for $delimiters.split( '', :skip-empty ) -> $open, $close {
        @openings.push: $open if $needle ~~ / $open /;
        @closings.push: $close if $needle ~~ / $close /;
    }

    @openings.join.say;
    @closings.join.say;

}



The article Perl Weekly Challenge 131: no coffee, no elegance has been posted by Luca Ferrari on September 20, 2021