TWC359

Challenge Link

Task1

We keep on summing the digits of the number until we reach a number with a single digit:

#!/usr/bin/env perl
use strict;
use warnings;
use List::Util qw(sum0);

sub digital_root {
  my ($n) = @_;
  my $c = 0;
  $c++, $n = sum0 split '',$n while $n > 9;
  printf "Persistence  = %d\nDigital Root = %d\n",$c,$n
}

digital_root(38);
digital_root(7);
digital_root(999);
digital_root(1999999999);
digital_root(101010);

Task2

We keep on removing duplicate characters until there's none:

#!/usr/bin/env perl
use strict;
use warnings;

sub string_reduction{
  my ($s) = @_;
  1 while $s =~ s/(\w)\1//g;
  $s
}

printf "%s\n",string_reduction('aabbccdd');
printf "%s\n",string_reduction('abccba');
printf "%s\n",string_reduction('abcdef');
printf "%s\n",string_reduction('aabbaeaccdd');
printf "%s\n",string_reduction('mississippi');