TWC310

Challenge Link

Task1

We take the intersection of arrays:

#!/usr/bin/env perl
use strict;
use warnings;
use Data::Show;
use Set::Scalar;

sub arrays_intersection{
  my ($arr) = @_;
  return () unless @$arr;
  my $s = Set::Scalar->new($arr->[0]->@*);
  map{$s *= Set::Scalar->new(@$_)} @{$arr}[1..$#$arr];
  $s->elements
}

print show arrays_intersection([[1,2,3,4],[4,5,6,1],[4,2,1,3]]);
print show arrays_intersection([[1,0,2,3],[2,4,5]]);
print show arrays_intersection([[1,2,3],[4,5],[6]]);

Task2

We sort the array based on even and odd indices:

#!/usr/bin/env perl
use strict;
use warnings;
use List::Util qw(mesh);
use Data::Show;

sub sort_even_odd{
  grep {defined}
    (mesh[sort{$a <=> $b}@{$_[0]}[grep{!($_%2)} 0..$#{$_[0]}]],
     [sort{$b <=> $a}@{$_[0]}[grep{$_%2} 0..$#{$_[0]}]]);
}

print show sort_even_odd([4,1,2,3]);
print show sort_even_odd([3,1]);
print show sort_even_odd([5,3,2,1,4]);