Perl Weekly Challenge 304: am I lazy?

This post presents my solutions to the Perl Weekly Challenge 304.
I keep doing the Perl Weekly Challenge in order to mantain my coding skills in good shape, as well as in order to learn new things, with particular regard to Raku, a language that I love.
This week, I solved the following tasks:

• PWC 304 - Task 1 - Raku
• PWC 304 - Task 2 - Raku

I’m a little lazy (and busy) in this period, hence I’m proposing only Raku solutions for this challenge.

Raku Implementations

PWC 304 - Task 1 - Raku Implementation

Given an array of bits and a positive number, see if it is possible to flip a 0 into a 1 so that no two 1s are consecutive and the number of flips is the specified positive number.

sub MAIN( Int $n, *@bits is copy where { $n > 0 && @bits.elems == @bits.grep( * ~~ /<[01]>/ ).elems } ) {

    my $changes-to-do = $n;

    for 1 ..^ @bits.elems - 2 -> $index {
		if ( @bits[ $index - 1 ] != 1 && @bits[ $index + 1 ] != 1 ) {
		    @bits[ $index ] = 1;
		    $changes-to-do--;
		}
    }

    'True'.say and exit if ( $changes-to-do <= 0);
    'False'.say;
}

The idea is simple: I iterate over all the elements of the array (excluding the boundaries) and try to flip an element if the preceeding and following ones are not already a 1. Since I do the change in place, because @bits is traited with is copy, I’m able to examine also the already flips at every loop. If the $changes-to-do has reached zero (or less), the script was succesful.

PWC 304 - Task 2 - Raku Implementation

Given an array of integers and a positive number, find out the subarray of consecutive elements with the same size as the specified number and that have the maximized average.

sub MAIN( Int $n, *@numbers where { 0 < $n <= @numbers.elems } ) {

    my @result = 0;

    for 0 ..^ @numbers.elems - $n -> $index {
		my $current-avg   = ( [+] @numbers[ $index .. $index + $n - 1 ] ) / $n;
		my $previous-avg =  ( [+] @result ) / $n;
		@result = @numbers[ $index .. $index + $n - 1 ] if ( $current-avg > $previous-avg );
    }

    ( ( [+] @result ) / $n ).say;
}

At every iteration over the array I consider a subarray, and compute its average. I compare the average with that of the @result array, which initially is filled with a single zero so to give an average of zero too. In the end, I recompute the average and print it out. Note that for caching reasons, it would have been better to store the average computations into variables.