TWC312

Challenge Link

Task1

We calculate the distance by keeping track of the last letter written:

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

sub minimum_time{
  my ($str) = @_;
  my ($res,$prev) = (0,0);
  foreach my $c(split '',$str){
    my $curr = ord($c) - ord('a');
    my $t = abs($prev - $curr);
    $t = min($t,26-$t);
    $res += $t+1;
    $prev = $curr
  }
  $res
}

printf "%d\n",minimum_time('abc');
printf "%d\n",minimum_time('bza');
printf "%d\n",minimum_time('zjpc');

Task2

We check if a box contains balls of all the three given colors:

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

sub balls_and_boxes{
  my ($sum,%h) = (0);
  $h{$2} .= $1 while($_[0] =~ /([RGB])(\d)/g);
  foreach my $v(values %h){
    $sum++ if all{index($v,$_) != -1} ('R','G','B')
  }
  $sum
}

printf "%d\n",balls_and_boxes('G0B1R2R0B0');
printf "%d\n",balls_and_boxes('G1R3R6B3G6B1B6R1G3');
printf "%d\n",balls_and_boxes('B3B2G1B3');

TWC311

Challenge Link

Task1

We swap the case of each letter in the string:

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

sub upper_lower{
  $_[0] =~ tr/A-Za-z/a-zA-Z/r
}

printf "%s\n",upper_lower('pERl');
printf "%s\n",upper_lower('rakU');
printf "%s\n",upper_lower('PyThOn');

Task2

We sum the digits of each group while the length of the string is greater than n:

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

sub group_digit_sum{
  my ($str,$n) = @_;
  while(length $str > $n){
    my @gps = unpack("(A$n)*",$str);
    $str = join('',map{sum0 split '',$_} @gps)
  }
  $str
}

printf "%s\n",group_digit_sum('111122333',3);
printf "%s\n",group_digit_sum('1222312',2);
printf "%s\n",group_digit_sum('100012121001',4);

TWC310

Challenge Link

Task1

We take the intersection of arrays:

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

sub arrays_intersection{
  my ($arr) = @_;
  return () unless @$arr;
  my $s = Set::Scalar->new($arr->[0]->@*);
  map{$s *= Set::Scalar->new(@$_)} @{$arr}[1..$#$arr];
  $s->elements
}

print show arrays_intersection([[1,2,3,4],[4,5,6,1],[4,2,1,3]]);
print show arrays_intersection([[1,0,2,3],[2,4,5]]);
print show arrays_intersection([[1,2,3],[4,5],[6]]);

Task2

We sort the array based on even and odd indices:

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

sub sort_even_odd{
  grep {defined}
    (mesh[sort{$a <=> $b}@{$_[0]}[grep{!($_%2)} 0..$#{$_[0]}]],
     [sort{$b <=> $a}@{$_[0]}[grep{$_%2} 0..$#{$_[0]}]]);
}

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

TWC309

Challenge Link

Task1

We look for the minimum difference between the pairs and return the found index:

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

sub min_gap{
  my ($arr) = @_;
  my $min = $arr->[0];
  my $min_gap = $arr->[1] - $arr->[0];
  foreach my $i(2..$#$arr){
    my $gap = $arr->[$i] - $arr->[$i-1];
    if($gap < $min_gap){
      $min = $arr->[$i];
      $min_gap = $gap
    }
  }
  $min
}

printf "%d\n",min_gap([2,8,10,11,15]);
printf "%d\n",min_gap([1,5,6,7,14]);
printf "%d\n",min_gap([8,20,25,28]);

Task2

We find the minimum difference of any two elements:

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

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

printf "%d\n",min_diff([1,5,8,9]);
printf "%d\n",min_diff([9,4,1,7]);

TWC304

Challenge Link

Task1

We count the consecutive pairs of zeros and check if the count is greater than the given n:

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

sub arrange_binary{
  my $c = 0;
  map{$c++ if $_[0]->[$_] == 0 && $_[0]->[$_+1] == 0} 0..$#{$_[0]}-1;
  $c > $_[1]
}

printf "%d\n",arrange_binary([1,0,0,0,1],1);
printf "%d\n",arrange_binary([1,0,0,0,1],2);

Task2

We find the maximum sub array sum of the given length n:

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

sub maximum_average{
  my ($arr,$n) = @_;
  my $max = min @$arr;
  foreach my $start(0..@$arr-$n){
    my $subsum = sum0(@{$arr}[$start..$start+$n-1]);
    my $avg = $subsum / $n;
    $max = $avg if $avg > $max
  }
  $max
}

say maximum_average([1,12,-5,-6,50,3],4);
say maximum_average([5],1);

TWC308

Challenge Link

Task1

We find the intersection of two arrays:

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

sub count_common{
  my %h;
  $h{$_}++ for @{$_[0]};
  scalar grep{exists $h{$_} && $h{$_}++ < 2} @{$_[1]}
}

printf "%d\n",count_common(['perl','weekly','challenge'],
			   ['raku','weekly','challenge']);
printf "%d\n",count_common(['perl','raku','python'],
			   ['python','java']);
printf "%d\n",count_common(['guest','contribution'],
			   ['fun','weekly','challenge']);

Task2

We find the resultant array by xoring the elements starting with the given first:

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

sub decode_xor{
  my @res = ($_[1]);
  push @res,$res[-1] ^ $_ foreach @{$_[0]};
  @res
}

print show decode_xor([1,2,3],1);
print show decode_xor([6,2,7,3],4);

TWC307

Challenge Link

Task1

We sort the array and return those indices where elements differ:

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

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

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

Task2

We find the anagrams by sorting each string and counting any differing two consecutive elements:

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

sub find_anagrams{
  my ($arr) = @_;
  my @sorted = map {join'',sort split ''} @$arr;
  my $sum = 1;
  map{$sum++ if $sorted[$_-1] ne $sorted[$_]} 1..$#sorted;
  $sum
}

printf "%d\n",find_anagrams(['acca','dog','god','perl','repl']);
printf "%d\n",find_anagrams(['abba','baba','aabb','ab','ab']);