TWC352

Challenge Link

Task1

We return every string that is a substring of amother:

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

sub match_string{
  my ($arr) = @_;
  my @res;
  foreach my $i(0..$#$arr) {
    my $x = $arr->[$i];
    foreach my $j(0..$#$arr) {
      my $y = $arr->[$j];
      if($i != $j && index($y,$x) != -1 && !any{$_ eq $x} @res) {
	push @res,$x;
	last
      }
    }
  }
  @res
}

printf "(%s)\n",join ', ',match_string(['cat','cats','dog','dogcat',
				       'dogcat','rat','ratcatdogcat']);
printf "(%s)\n",join ', ',
  match_string(['hello','hell','world','wor','ellow','elloworld']);
printf "(%s)\n",join ', ',
  match_string(['a', 'aa', 'aaa', 'aaaa']);
printf "(%s)\n",join ', ',
  match_string(['flower','flow','flight','fl','fli','ig','ght']);
printf "(%s)\n",join ', ',
  match_string(['car','carpet','carpenter','pet',
		'enter','pen','pent']);

Task2

We check if the accumulated binary number is divisible by 5 and accumulate the boolean results in an array:

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

sub binary_prefix{
  my @res;
  my $x = 0;
  foreach(@{$_[0]}){
    $x = ($x << 1 | $_) % 5;
    push @res,$x == 0 ? 1 : 0;
  }
  @res
}

printf "(%s)\n", join ', ', binary_prefix([0,1,1,0,0,1,0,1,1,1]);
printf "(%s)\n", join ', ', binary_prefix([1,0,1,0,1,0]);
printf "(%s)\n", join ', ', binary_prefix([0,0,1,0,1]);
printf "(%s)\n", join ', ', binary_prefix([1,1,1,1,1]);
printf "(%s)\n", join ', ', binary_prefix([1,0,1,1,0,1,0,0,1,1]);

TWC351

Challenge Link

Task1

We sort the array and remove the minimum and maximum elements then take the average:

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

sub special_average{
  my ($arr) = @_;
  return 0 if @$arr < 2;
  @$arr = sort {$a <=> $b} @$arr;
  my @sub = splice @$arr,1,$#$arr-1;
  (sum0 @sub) / @sub
}

printf "%d\n",special_average([8000,5000,6000,2000,3000,7000]);
printf "%d\n",special_average([100_000,80_000,110_000,90_000]);
printf "%d\n",special_average([2500,2500,2500,2500]);
printf "%d\n",special_average([2000]);
printf "%d\n",special_average([1000,2000,3000,4000,5000,6000]);

Task2

We sort the array and then check if the distance of all elements is the same:

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

sub arithmetic_progression{
  my ($arr) = @_;
  @$arr = sort {$a <=> $b} @$arr;
  my $d = abs(shift(@$arr) - shift(@$arr));
  for(my $i = 0; $i < $#$arr-1; ++$i){
    return 0 if abs($arr->[$i] - $arr->[$i+1]) != $d
  }
  1
}

printf "%d\n",arithmetic_progression([1,3,5,7,9]);
printf "%d\n",arithmetic_progression([9,1,7,5,3]);
printf "%d\n",arithmetic_progression([1,2,4,8,16]);
printf "%d\n",arithmetic_progression([5,-1,3,1,-3]);
printf "%d\n",arithmetic_progression([1.5,3,0,4.5,6]);

TWC350

Challenge Link

Task1

We count all strings of length 3 with no repeating characters:

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

sub good_substrings{
  scalar grep {!/(.).*\1/} $_[0] =~ /(?=(...))/g
}

printf "%d\n",good_substrings('abcaefg');
printf "%d\n",good_substrings('xyzzabc');
printf "%d\n",good_substrings('aababc');
printf "%d\n",good_substrings('qwerty');
printf "%d\n",good_substrings('zzzaaa');

Task2

We find all shuffle pairs between the given ranges:

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

sub shuffle_pairs{
  my ($from,$to,$count) = @_;
  my $found = 0;
  foreach my $n($from..$to){
    my $c = 0;
    my $s = join '',sort split '',$n;
    foreach my $w(2..9){
      my $m = $n * $w;
      next if length $m > length $n;
      next if $s ne join '',sort split '',$m;
      ++$c
    }
    ++$found if $c >= $count
  }
  $found
}

printf "%d\n",shuffle_pairs(1,1000,1);
printf "%d\n",shuffle_pairs(1500,2500,1);
printf "%d\n",shuffle_pairs(1_000_000,1_500_000,5);
printf "%d\n",shuffle_pairs(13_427_000,14_100_000,2);
printf "%d\n",shuffle_pairs(1030,1130,1);