TWC266

Challenge Link

 Task1

We count the words in a hash, then check which one's count is equal to one, and sort them:

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

sub uncommon_words{
  my %h;
  $h{lc $_}++ foreach split /\W+/, $_[0] . ' ' . $_[1];
  sort grep{$h{$_} == 1} keys %h;
}

print show uncommon_words('Mango is sweet','Mango is sour');
print show uncommon_words('Mango Mango','Orange');
print show uncommon_words('Mango is Mango','Orange is Orange');

Task2

In an NxN square matrix, if the indices i and j are equal then we are on the main diagonal, and if the sum of i and j is equal to N-1, then we are on the anti-diagonal, and if these conditions are true, then we shouldn't see a 0 and if we do we return 0 immediately, and if the above 2 conditions is not met, then we must see a zero since we are not on the diagonals. If the function doesn't return inside the loops then we definitely have an X matrix:

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

sub x_matrix{
  my ($mat) = @_;
  my $n = @$mat;
  foreach my $i(0..$n-1){
    foreach my $j(0..$n-1){
      if($i == $j || $i+$j == $n-1){
	return 0 if $mat->[$i][$j] == 0
      }
      elsif($mat->[$i][$j] != 0){return 0}
    }
  }
  1
}

printf "%d\n",x_matrix([[1,0,0,2],
			[0,3,4,0],
			[0,5,6,0],
			[7,0,0,1]]);

printf "%d\n",x_matrix([[1,2,3],
			[4,5,6],
			[7,8,9]]);

printf "%d\n",x_matrix([[1,0,2],
			[0,3,0],
			[4,0,5]]);

TWC265

Challenge Link

Task1

We see if the element count of an item is greater than or equal to 33% of the whole array size:

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

sub thirty_three_percent_appearance{
  my %h;
  $h{$_}++ foreach @{$_[0]};
  min grep{$h{$_} if $h{$_} >= (@{$_[0]}/3)}keys %h;
}

printf "%d\n",thirty_three_percent_appearance([1,2,3,3,3,3,4,2]);
printf "%d\n",thirty_three_percent_appearance([1,1]);
printf "%d\n",thirty_three_percent_appearance([1,2,3]);

Task2

We check if the given string is a subset of any of the given strings in the array:

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

sub completing_word{
  my $s1 = Set::Scalar->new(split'',(lc $_[0] =~ s/(\s+|\d+)//gr));
  (grep{$_ if $s1 <= (Set::Scalar->new(split'',$_))}@{$_[1]})[0];
}

printf "%s\n",completing_word('aBc 11c',['accbbb','abc','abbc']);
printf "%s\n",completing_word('Da2 abc',['abcm','baacd','abaadc']);
printf "%s\n",completing_word('JB 007',['jj','bb','bjb']);

TWC264

Challenge Link

Task1

We make two sets of lowercase and uppercase letters and find their intersection:

#!/usr/local/bin/env perl
use strict;
use warnings;
use Set::Scalar;
use List::Util qw(maxstr);

sub greatest_english_letter{
  my $s1 = Set::Scalar->new;
  my $s2 = Set::Scalar->new;
  map{$_ le 'Z' ? $s1->insert($_) : $s2->insert(uc $_)} split '',$_[0];
  maxstr($s1->intersection($s2)->members) // ''
}

printf "%s\n", greatest_english_letter('PeRlwEeKLy');
printf "%s\n", greatest_english_letter('ChaLlenge');
printf "%s\n", greatest_english_letter('The');

Task2

We insert the elements at appropriate indices as per the given instructions:

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

sub target_array{
  my @ret;
  splice @ret,$_[1]->[$_],0,$_[0]->[$_] foreach(0..$#{$_[1]});
  @ret
}

print show target_array([0,1,2,3,4],[0,1,2,2,1]);
print show target_array([1,2,3,4,0],[0,1,2,3,0]);
print show target_array([1],[0]);

TWC263

Challenge Link

Task1

We sort the array then return the indices of the elements equal to k:

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

sub target_index{
  my @sorted = sort{$a <=> $b} @{$_[0]};
  map{$sorted[$_] == $_[1] ? $_ : ()}0..$#{$_[0]};
}

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

Task2

We add each quantity to the count of ids in the hash and return the keys and values of the hash:

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

sub merge_items{
  my %h;
  $h{$_->[0]} += $_->[1] foreach(@{$_[0]},@{$_[1]});
  map{[$_,$h{$_}]} sort{$a <=> $b} keys %h;
}

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

TWC262

Challenge Link

Task1

We count the number of negative and positive numbers in the array and return the maximum:

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

sub max_positive_negative{
  my ($neg,$pos) = 0 x 2;
  map{$neg++ if $_ < 0;$pos++ if $_ > 0}@{$_[0]};
  max $neg,$pos
}

printf "%d\n",max_positive_negative([-3,1,2,-1,3,-2,4]);
printf "%d\n",max_positive_negative([-1,-2,-3,1]);
printf "%d\n",max_positive_negative([1,2]);

Task2

For each (i,j) pair we check if the condition (i * j mod k == 0) holds and count them:

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

sub count_equal_divisible{
  my ($arr,$k) = @_;
  my $count = 0;
  foreach my $i(0..@$arr-2){
    foreach my $j($i+1..@$arr-1){
      ++$count if $arr->[$i] == $arr->[$j] && ($i*$j) % $k == 0
    }
  }
  $count
}

printf "%d\n",count_equal_divisible([3,1,2,2,2,1,3],2);
printf "%d\n",count_equal_divisible([1,2,3],1);

TWC261

Challenge Link

Task1

We subtract the sum of each digit in each number from the sum of the numbers and take its absolute value:

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

sub element_digit_sum{
  abs(sum0(map{split ''}@{$_[0]}) - sum0(@{$_[0]}))
}

printf "%d\n",element_digit_sum([1,2,3,45]);
printf "%d\n",element_digit_sum([1,12,3]);
printf "%d\n",element_digit_sum([1,2,3,4]);
printf "%d\n",element_digit_sum([236,416,336,350]);

Task2

While $start is in the list, we keep multiplying it by 2:

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

sub multiply_by_two{
  my ($arr,$start) = @_;
  $start *= 2 while((firstidx{$start == $_}@$arr)!=-1);
  $start
}

printf "%d\n",multiply_by_two([5,3,6,1,12],3);
printf "%d\n",multiply_by_two([1,2,4,3],1);
printf "%d\n",multiply_by_two([5,6,7],2);

TWC260

Challenge Link

Task1

We count the occurrences of each integer in a hash, then check if the length of the values of that hash is equal to the length of the unique values,  if so we return 1 else 0:

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

sub unique_occurences{
  my %h;
  $h{$_}++ foreach @{$_[0]};
  my @values = values %h;
  @values == (uniq @values) || 0
}

printf "%d\n",unique_occurences([1,2,2,1,1,3]);
printf "%d\n",unique_occurences([1,2,3]);
printf "%d\n",unique_occurences([-2,0,1,-2,1,1,0,1,-2,9]);

Task2

We construct an array of all permutations of the given string, join each tuple to a string, and remove the duplicates, then sort and find the index of the string which is equal to the argument of the subroutine:

#!/usr/bin/env perl
use strict;
use warnings;
use Algorithm::Combinatorics qw(permutations);
use List::MoreUtils qw(onlyidx uniq);

sub dictionary_rank{
  1+onlyidx{$_ eq $_[0]}
    sort{$a cmp $b}
    uniq map{join'',@$_}
    permutations([split '',$_[0]])
}

printf "%d\n",dictionary_rank('CAT');
printf "%d\n",dictionary_rank('GOOGLE');
printf "%d\n",dictionary_rank('SECRET');