TL;DR

On with TASK #2 from The Weekly Challenge #228. Enjoy!

The challenge

You are given an array of integers in which all elements are unique.

Write a script to perform the following operations until the array is empty and return the total count of operations.

If the first element is the smallest then remove it otherwise move it to the end.

Example 1

Input: @int = (3, 4, 2)
Ouput: 5

Operation 1: move 3 to the end: (4, 2, 3)
Operation 2: move 4 to the end: (2, 3, 4)
Operation 3: remove element 2: (3, 4)
Operation 4: remove element 3: (4)
Operation 5: remove element 4: ()

Example 2

Input: @int = (1, 2, 3)
Ouput: 3

Operation 1: remove element 1: (2, 3)
Operation 2: remove element 2: (3)
Operation 3: remove element 3: ()

The questions

Alas, this time no question, apart from lazyness: how big do we expect this array to be? Let’s assume that it’s not too big…

The solution

This challenge has all the looks of something with a clever solution, but it didn’t dawn on me so here we are with the laziest solution possible.

We first sort the array, so that we have a reference of when an item can get out of the main one. As soon as we find the right element, we just ditch it from both arrays; otherwise we do the cycling trick on the main one and move on.

Perl goes first:

#!/usr/bin/env perl
use v5.24;
use warnings;
use experimental 'signatures';

say empty_array(@ARGV);

sub empty_array (@ints) {
   my @sorted = sort { $a <=> $b } @ints;
   my $n = 0;
   while (@ints) {
      my $item = shift @ints;
      if ($item == $sorted[0]) { shift @sorted     }
      else                     { push @ints, $item }
      ++$n;
   }
   return $n;
}

Raku is pretty much the translation:

#!/usr/bin/env raku
use v6;
sub MAIN (*@args) { put empty-array(@args».Int) }

sub empty-array (@ints is copy) {
   my @sorted = @ints.sort;
   my $n = 0;
   while @ints {
      my $item = @ints.shift;
      if $item == @sorted[0] { @sorted.shift     }
      else                   { @ints.push: $item }
      ++$n;
   }
   return $n;
}

Stay safe and cheers!