From 4017ec0ffb3b249c16468d19cee0ca295e15c138 Mon Sep 17 00:00:00 2001 From: Alexander Pankoff Date: Thu, 2 Dec 2021 18:26:46 +0100 Subject: Add solution for challenge-141 task 1 --- challenge-141/alexander-pankoff/perl/ch-1.pl | 63 ++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 challenge-141/alexander-pankoff/perl/ch-1.pl diff --git a/challenge-141/alexander-pankoff/perl/ch-1.pl b/challenge-141/alexander-pankoff/perl/ch-1.pl new file mode 100644 index 0000000000..bb4a1b6fb2 --- /dev/null +++ b/challenge-141/alexander-pankoff/perl/ch-1.pl @@ -0,0 +1,63 @@ +use strict; +use warnings; +use feature qw'say signatures'; +no warnings 'experimental::signatures'; + +use constant DEBUG => $ENV{DEBUG} // 0; + +run() unless caller(); + +sub run() { + say join( ' ', find_k_lowest_integers_with_exactly_n_divisors( 10, 8 ) ); +} + +sub find_k_lowest_integers_with_exactly_n_divisors ( $k, $n ) { + my @out; + + for ( my $i = 1 ; @out < $k ; $i++ ) { + my @divisors = find_divisors($i); + if ( @divisors == $n ) { + push @out, $i; + explain( $i, scalar @out, @divisors ) if DEBUG; + } + } + return @out; +} + +sub find_divisors($x) { + my @out; + for ( my $i = 1 ; $i <= int( $x / 2 ) ; $i++ ) { + push @out, $i if $x % $i == 0; + } + + push @out, $x; + + return @out; +} + +sub explain ( $x, $count, @divisors ) { + say "$x is the " + . to_ordinal($count) + . " such number having exactly " + . scalar @divisors + . " divisors."; + say join( ", ", @divisors ); + +} + +sub to_ordinal($x) { + my %map = ( + 1 => 'first', + 2 => 'second', + 3 => 'third', + 4 => 'fourth', + 5 => 'fifth', + 6 => 'sixth', + 7 => 'seventh', + 8 => 'eigth', + 9 => 'nineth', + 10 => 'tenth', + ); + + return $map{$x} // $x . 'th'; +} -- cgit From 48f2afa206bbcd528658c4b3bdb73afb6e48f41f Mon Sep 17 00:00:00 2001 From: Alexander Pankoff Date: Thu, 2 Dec 2021 18:59:35 +0100 Subject: Add solution for challenge-141 task 2 --- challenge-141/alexander-pankoff/perl/ch-2.pl | 49 ++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 challenge-141/alexander-pankoff/perl/ch-2.pl diff --git a/challenge-141/alexander-pankoff/perl/ch-2.pl b/challenge-141/alexander-pankoff/perl/ch-2.pl new file mode 100644 index 0000000000..a2d1d0bea6 --- /dev/null +++ b/challenge-141/alexander-pankoff/perl/ch-2.pl @@ -0,0 +1,49 @@ +use strict; +use warnings; +use feature qw'say signatures'; +no warnings 'experimental::signatures'; + +use List::Util qw(reduce); + +use constant DEBUG => $ENV{DEBUG} // 0; + +run() unless caller(); + +sub run() { + my $m = prompt_for_integer('m'); + my $n = prompt_for_integer('n'); + + my @possible_integers = numbers_from_digits($m); + my @divisible_by_n = grep { $_ % $n == 0 } @possible_integers; + say scalar @divisible_by_n; +} + +sub numbers_from_digits($x) { + my @digits = split( '', $x ); + my $numbers = reduce( + sub { + my $digit = $digits[$b]; + return [ + @$a, # + $digit, + ( grep { length $_ < @digits } map { $_ . $digit } @$a ), + ]; + }, + [], + 0 .. $#digits + ); + + return @$numbers; +} + +sub prompt_for_integer($name) { + say "Enter positive integer '$name'"; + chomp( my $number = ); + + if ( $number !~ m/^\d+$/ || $number < 1 ) { + say "Invalid integer."; + return prompt_for_integer($name); + } + + return $number; +} -- cgit From 425892a3af4eff1595cbfa3de7928ce2d3b0f577 Mon Sep 17 00:00:00 2001 From: Alexander Pankoff Date: Thu, 2 Dec 2021 19:13:21 +0100 Subject: Optimize find_divisors --- challenge-141/alexander-pankoff/perl/ch-1.pl | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/challenge-141/alexander-pankoff/perl/ch-1.pl b/challenge-141/alexander-pankoff/perl/ch-1.pl index bb4a1b6fb2..bc2e50f85c 100644 --- a/challenge-141/alexander-pankoff/perl/ch-1.pl +++ b/challenge-141/alexander-pankoff/perl/ch-1.pl @@ -25,13 +25,17 @@ sub find_k_lowest_integers_with_exactly_n_divisors ( $k, $n ) { } sub find_divisors($x) { + return 1 if $x == 1; my @out; - for ( my $i = 1 ; $i <= int( $x / 2 ) ; $i++ ) { - push @out, $i if $x % $i == 0; + my $max = $x; + for ( my $i = 1 ; $i < $max ; $i++ ) { + if ( $x % $i == 0 ) { + $max = $x / $i; + push @out, $i; + push @out, $max if $i != $max; + } } - push @out, $x; - return @out; } @@ -41,7 +45,7 @@ sub explain ( $x, $count, @divisors ) { . " such number having exactly " . scalar @divisors . " divisors."; - say join( ", ", @divisors ); + say join( ", ", sort { $a <=> $b } @divisors ); } -- cgit From 776c785fa7ed7a77a9ff8fc84d06307cba246482 Mon Sep 17 00:00:00 2001 From: Alexander Pankoff Date: Fri, 3 Dec 2021 09:11:43 +0100 Subject: Add debug/explain mode to challenge 141 task 02 --- challenge-141/alexander-pankoff/perl/ch-2.pl | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/challenge-141/alexander-pankoff/perl/ch-2.pl b/challenge-141/alexander-pankoff/perl/ch-2.pl index a2d1d0bea6..188ca57823 100644 --- a/challenge-141/alexander-pankoff/perl/ch-2.pl +++ b/challenge-141/alexander-pankoff/perl/ch-2.pl @@ -15,9 +15,22 @@ sub run() { my @possible_integers = numbers_from_digits($m); my @divisible_by_n = grep { $_ % $n == 0 } @possible_integers; + + explain( $m, $n, \@possible_integers, \@divisible_by_n ) if DEBUG; say scalar @divisible_by_n; } +sub explain ( $m, $n, $possible_integers, $divisible_by_n ) { + + say "Possible integers created using the digits of $m are:"; + say join( ', ', sort { $a <=> $b } @$possible_integers ); + + say "There are " + . scalar(@$divisible_by_n) + . " integers divisible by $n such as:"; + say join( ', ', sort { $a <=> $b } @$divisible_by_n ); +} + sub numbers_from_digits($x) { my @digits = split( '', $x ); my $numbers = reduce( -- cgit