TWC384

Challenge Link

Task1

Simple base conversion:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub base_n{
  my ($num,$base) = @_;
  my @chars = ('0'..'9','A'..'Z','a'..'z','+','/');
  my @digits;
  if($num == 0){
    @digits = (0);
  } else {
    while($num > 0){
      unshift @digits,$num % $base;
      $num = int($num / $base)
    }
  }
  join '',map{$chars[$_]} @digits
}

is base_n(42,2),'101010','Example 1';
is base_n(15642094,16),'EEADEE','Example 2';
is base_n(493,8),'755','Example 3';
is base_n(2228519,36),'1BRJB','Example 4';
is base_n(123456789,64),'7MyqL','Example 5';

done_testing();

Task2

We enumerate each candidate and find ones which have equal length and same number of zeros and ones:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub special_binary_substrings {
  my ($b) = @_;
  my @m;
  foreach my $pos(0..length($b)-1){
    foreach my $len(2..length($b) - $pos) {
      my $sub = substr($b,$pos,$len);
      next unless $sub =~ /^(0+1+|1+0+)$/;
      my ($f,$s) = $sub =~ /^(0+)(1+)$/ 
	? ($1,$2) 
	: $sub =~ /^(1+)(0+)$/;
      push @m, $sub if length($f) == length($s);
    }
  }
  \@m;
}

is_deeply special_binary_substrings('0101'),
  ['01','10','01'],'Example 1';
is_deeply special_binary_substrings('000111'),
  ['000111','0011','01'],'Example 2';
is_deeply special_binary_substrings('000011'),
  ['0011','01'],'Example 3';
is_deeply special_binary_substrings('10011100'),
  ['10','0011','01','1100','10'],'Example 4';
is_deeply special_binary_substrings('00000'),[],'Example 5';

done_testing();

TWC383

Challenge Link

Task1

We check if elements belong to the same synonym group:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub similar_list{
  return 0 unless @{$_[0]} == @{$_[1]};
 OUTER:
  foreach my $i(0..$#{$_[0]}){
    next OUTER if $_[0]->[$i] eq $_[1]->[$i];
    foreach my $sub(@{$_[2]}){
      next OUTER if in($_[0]->[$i],$sub) &&
	in($_[1]->[$i],$sub)
      }
    return 0
  }
  1
}

sub in{
  my ($e,$l) = @_;
  grep {$_ eq $e} @$l
}

is similar_list(['great','acting'],
		['fine','drama'],
		[['great','fine'],
		 ['acting','drama']]),1,'Example 1';
is similar_list(['apple','pie'],
		['banana','pie'],
		[['apple','peach'],
		 ['peach','banana']]),0,'Example 2';
is similar_list(['perl4','python'],
		['raku','python'],
		[['perl4','perl5','raku']]),1,'Example 3';
is similar_list(['enjoy','challenge'],
		['love', 'weekly', 'challenge'],
		[['enjoy','love']]),0,'Example 4';
is similar_list(['fast','car'],
		['quick','vehicle'],
		[['quick','fast'],['vehicle','car']]),1,'Example 5';
done_testing();

Task2

We make the colors web safe according to the given rules:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub nearest_rgb{
  my @web_safe = (0,51,102,153,204,255);
  my ($r,$g,$b) = map hex,$_[0] =~ /#(..)(..)(..)/;
  my $safe = '#';
  foreach my $c($r,$g,$b) {
    my $best = 0;
    foreach my $s(@web_safe){
      $best = $s if abs($c - $s) < abs($best - $c)
    }
    $safe .= sprintf '%02X',$best
  }
  $safe
}

is nearest_rgb('#F4B2D1'),'#FF99CC','Example 1';
is nearest_rgb('#15E6E5'),'#00FFCC','Example 2';
is nearest_rgb('#191A65'),'#003366','Example 3';
is nearest_rgb('#2D5A1B'),'#336633','Example 4';
is nearest_rgb('#00FF66'),'#00FF66','Example 5';

done_testing();

TWC381

Challenge Link

Task1

We check if every row and column contains digits from 1 to n:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub same_row_column{
  my ($m) = @_;
  my $n = @$m;

  foreach my $row (@$m){
    my %h;
    foreach my $num(@$row){
      return 0 if ($num < 1 || $num > $n || $h{$num}++);
    }
  }
  
  foreach my $col(0..$n-1){
    my %h;
    foreach my $row(@$m){
      my $num = $row->[$col];
      return 0 if ($num < 1 || $num > $n || $h{$num}++);
    }
  }
  1
}

is same_row_column([[1,2,3,4],[2,3,4,1],
		    [3,4,1,2],[4,1,2,3]]),1,'Example 1';
is same_row_column([[1]]),1,'Example 2';
is same_row_column([[1,2,5],[5,1,2],[2,5,1]]),0,'Example 3';
is same_row_column([[1,2,3],[1,2,3],[1,2,3]]),0,'Example 4';
is same_row_column([[1,2,3],[3,2,1],[3,2,1]]),0,'Example 5';

done_testing();

Task2

We count the numbers which have strictly smaller and greater elements than themselves:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub smaller_greater_element{
  my ($arr) = @_;
  my ($min,$max) = ($arr->[0],$arr->[0]);
  ($_ < $min) ? ($min = $_)
    : ($max < $_) && ($max = $_) foreach @$arr;
  @$arr - grep {$min == $_ || $max == $_} @$arr
}

is smaller_greater_element([2,4]),0,'Example 1';
is smaller_greater_element([1,1,1,1]),0,'Example 2';
is smaller_greater_element([1,1,4,8,12,12]),2,'Example 3';
is smaller_greater_element([3,6,6,9]),2,'Example 4';
is smaller_greater_element([0,-5,10,-2,4]),3,'Example 5';

done_testing();

TWC377

Challenge Link

Task1

We check if a pair of chars exists in the reverse of the given string:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub reverse_existence{
  0 + $_[0] =~ /(?=(.)(.))(?=.*\2\1)/
}

is reverse_existence('abcba'),1,'Example 1';
is reverse_existence('racecar'),1,'Example 2';
is reverse_existence('abcd'),0,'Example 3';
is reverse_existence('banana'),1,'Example 4';
is reverse_existence('hello'),1,'Example 5';

done_testing();

Task2

We count strings which are both prefix and suffix of another one:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 6;

sub prefix_suffix{
  my ($arr) = @_;
  my %h;
  foreach my $i(0..$#$arr){
    my $s1 = $arr->[$i];
    foreach my $j($i+1..$#$arr){
      my $s2 = $arr->[$j];
      next if 0 != index($s2,$s1)
	|| abs(length($s2) - length($s1)) != rindex $s2,$s1;
      undef $h{join ':',sort {$a <=> $b} $i,$j}
    }
  }
  scalar keys %h
}

is prefix_suffix(['a','aba','ababa','aa']),4,'Example 1';
is prefix_suffix(['pa','papa','ma','mama']),2,'Example 2';
is prefix_suffix(['abao','ab']),0,'Example 3';
is prefix_suffix(['abab','abab']),1,'Example 4';
is prefix_suffix(['ab','abab','ababab']),3,'Example 5';
is prefix_suffix(['abc','def','ghij']),0,'Example 6';

done_testing();

TWC374

Challenge Link

Task1

We return the substrings which consists of vowels and has all 5 of them:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub count_vowel{
  my @res;
  my $len = length $_[0];
  foreach my $s(0..$len-1){
    foreach my $l(5..$len-$s){
      my $sub = substr($_[0],$s,$l);
      next unless $sub =~ /^[aeiou]+$/;
      next unless (5 == grep {$sub =~ /$_/} qw(a e i o u));
      push @res,$sub
    }
  }
  \@res
}

is_deeply count_vowel('aeiou'),['aeiou'],'Example 1';
is_deeply count_vowel('aaeeeiioouu'),
  ['aaeeeiioou','aaeeeiioouu','aeeeiioou','aeeeiioouu'],'Example 2';
is_deeply count_vowel('aeiouuaxaeiou'),
  ['aeiou','aeiouu','aeiouua','eiouua','aeiou'],'Example 3';
is_deeply count_vowel('uaeiou'),['uaeio','uaeiou','aeiou'],'Example 4';
is_deeply count_vowel('aeioaeioa'),[],'Example 5';

done_testing();

Task2

We group the digits and find the maximum:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub largest_same_digit_number{
  my $r = -1;
  while($_[0] =~ /((.)\2*)/g){
    $r = $1 if $r < $1
  }
  0 + $r
}

is largest_same_digit_number('6777133339'),3333,'Example 1';
is largest_same_digit_number('1200034'),4,'Example 2';
is largest_same_digit_number('44221155'),55,'Example 3';
is largest_same_digit_number('88888'),88888,'Example 4';
is largest_same_digit_number('11122233'),222,'Example 5';

done_testing();

TWC372

Challenge Link

Task1

We rearrange the spaces per the given instructions:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub rearrange_spaces{
  my $c = $_[0] =~ tr/ //;
  my @words = split ' ',$_[0];
  my $width = @words > 1 ? int($c / $#words) : 0;
  my $rest = @words > 1 ? $c % $#words : $c;
  join(' ' x $width,@words) . ' ' x $rest
}

is rearrange_spaces('  challenge  '),'challenge    ','Example 1';
is rearrange_spaces('coding  is  fun'),'coding  is  fun','Example 2';
is rearrange_spaces('a b c  d'),'a b c d ','Example 3';
is rearrange_spaces('  team      pwc  '),
  'team          pwc','Example 4';
is rearrange_spaces('   the  weekly  challenge  '),
  'the    weekly    challenge ','Example 5';

Task2

We find the largest substring in-between two equal characters:

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 5;

sub largest_string{
  my $l = 0;
  $l < length $2 and $l = length $2 while $_[0] =~ /(.)(?=(.*)\1)/g;
  $l
}

is largest_string('aaaaa'),3,'Example 1';
is largest_string('abcdeba'),5,'Example 2';
is largest_string('abbc'),0,'Example 3';
is largest_string('abcaacbc'),4,'Example 4';
is largest_string('laptop'),2,'Example 5';

TWC380

Challenge Link

Task1

We count the maximum frequencies of vowels and consonants and sum them:

#!/usr/bin/env perl
use strict;
use warnings;
use List::Util qw(max);
use Test::More tests => 5;

sub sum_of_frequencies {
  my %h;
  $h{$_}++ foreach split '', lc $_[0];
  my ($c, $v) = (0, 0);
  foreach (keys %h) {
    /[aeiou]/ ? ($v = max($v, $h{$_})) : ($c = max($c, $h{$_}));
  }
  $c + $v;
}

is sum_of_frequencies('banana'),5,'Example 1';
is sum_of_frequencies('teestett'),7,'Example 2';
is sum_of_frequencies('aeiouuaa'),3,'Example 3';
is sum_of_frequencies('rhythm'),2,'Example 4';
is sum_of_frequencies('x'),1,'Example 5';

Task2

We calculate the score of each letter according to its position in the string and reverse alphabet enumeration and then sum the result:

#!/usr/bin/env perl
use strict;
use warnings;
use List::Util qw(sum0);
use Test::More tests => 5;

sub reverse_degree{
  my ($i,%h) = (1);
  @h{'a'..'z'} = reverse 1..26;
  sum0 map {$h{$_} * $i++} split '',lc $_[0]
}

is reverse_degree('z'),1,'Example 1';
is reverse_degree('a'),26,'Example 2';
is reverse_degree('bbc'),147,'Example 3';
is reverse_degree('racecar'),560,'Example 4';
is reverse_degree('zyx'),14,'Example 5';

done_testing();