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| -rw-r--r-- | challenge-195/wlmb/blog.txt | 1 | ||||
| -rwxr-xr-x | challenge-195/wlmb/perl/ch-1.pl | 48 | ||||
| -rwxr-xr-x | challenge-195/wlmb/perl/ch-2.pl | 10 |
3 files changed, 59 insertions, 0 deletions
diff --git a/challenge-195/wlmb/blog.txt b/challenge-195/wlmb/blog.txt new file mode 100644 index 0000000000..a8e038bba3 --- /dev/null +++ b/challenge-195/wlmb/blog.txt @@ -0,0 +1 @@ +https://wlmb.github.io/2022/12/12/PWC195/ diff --git a/challenge-195/wlmb/perl/ch-1.pl b/challenge-195/wlmb/perl/ch-1.pl new file mode 100755 index 0000000000..d131e286e3 --- /dev/null +++ b/challenge-195/wlmb/perl/ch-1.pl @@ -0,0 +1,48 @@ +#!/usr/bin/env perl +# Perl weekly challenge 195 +# Task 1: Special Integers +# +# See https://wlmb.github.io/2022/12/12/PWC195/#task-1-special-integers +use v5.36; +use integer; +use POSIX qw(lround); +say(<<"FIN"), exit unless @ARGV; +Usage: $0 N1 [N2...] +to get the number of special numbers between 1 and Ni +FIN +say "$_->", special($_) for @ARGV; +sub fact($n){ # factorial + my $r=1; + $r*=$_ for (1..$n); + $r +} +sub special($n){ + my $k=0; + my $count=0; + while($k<=9 && 10**($k+1) < $n){ + # Count from 1 to 9, then from 10 to 99, then from 100 to 999, etc. + $count += 9*fact(9)/fact(9-$k); + ++$k; + } + return $count if $k>9; # Nothing else to do eleven digit numbers or larger + #Count from 100.. to q00..-1 + my $q=lround($n/10**$k); + $count += ($q-1)*fact(9)/fact(9-$k); + $count += final($q, $k-1, $n); # count from q00... upto $n=qxy... + return $count; +} +sub final($left, $power, $n){ # final approach from left 0 0 0 to n=x y z + my $count=0; + my $fixed=length $left; # leftward fixed digits + my %fixed; + ++$fixed{$_} for my @fixed=split '', $left; # actual fixed digits. + $_>1 && return 0 for(values %fixed); # nothing to add if fixed part is not special + return 1 if $power < 0; # Found last string + my $target=substr($n, $fixed, 1); # Next digit + for(0..$target-1){ # count upwards to target + next if $fixed{$_}; # skip seen digits + $count += fact(9-$fixed)/fact(9-$fixed-$power); # add rightwards contribution + } + $count += final($left.$target, $power-1, $n); # add digit to leftmost and recurse. + return $count; +} diff --git a/challenge-195/wlmb/perl/ch-2.pl b/challenge-195/wlmb/perl/ch-2.pl new file mode 100755 index 0000000000..c4dfa29c27 --- /dev/null +++ b/challenge-195/wlmb/perl/ch-2.pl @@ -0,0 +1,10 @@ +#!/usr/bin/env perl +# Perl weekly challenge 195 +# Task 2: Most Frequent Even +# +# See https://wlmb.github.io/2022/12/12/PWC195/#task-2-most-frequent-even +use v5.36; +my %count; +$count{$_}++ for grep {!($_&1)} @ARGV; # Filter evens and count them +my @sorted=sort {$count{$b} <=> $count{$a} || $a<=>$b} keys %count; +say join " ", @ARGV, " -> ", @sorted?shift @sorted:-1 |