Merge pull request #3443 from wlmb/challenges

Solutions to challenge 98

3 files changed, 70 insertions, 0 deletions

diff --git a/challenge-098/wlmb/blog.txt b/challenge-098/wlmb/blog.txt
new file mode 100644
index 0000000000..6a08f68483
--- /dev/null
+++ b/challenge-098/wlmb/blog.txt
@@ -0,0 +1 @@
+https://wlmb.github.io/2021/02/01/PWC098/
diff --git a/challenge-098/wlmb/perl/ch-1.pl b/challenge-098/wlmb/perl/ch-1.pl
new file mode 100755
index 0000000000..0f7dd8dc13
--- /dev/null
+++ b/challenge-098/wlmb/perl/ch-1.pl
@@ -0,0 +1,54 @@
+#!/usr/bin/env perl
+# Perl weekly challenge 098
+# Task 1: Read N characters
+#
+# See https:/wlmb.github.io/2021/02/01/PWC098/#task-1-read-n-characters
+use warnings;
+use strict;
+use v5.12;
+use Scalar::Util qw(looks_like_number);
+use List::Util qw(all);
+
+sub readN { # find and call the appropriate reader with the appropriate argument
+    my $filename=shift;
+    my $number=shift;
+    return reader($filename)->($number); #get the appropriate reader to read
+}
+
+
+sub reader { #returns a reader, maybe creating it.
+    state %reader; #hash of readers, one per seen filename
+    my $filename=shift;
+    $reader{$filename} //=new_reader($filename);
+}
+
+sub new_reader {#create a new reader
+    my $filename=shift;
+    open my $fh, "<", $filename or die "Couldn't open $filename: $!";
+    my $line=""; #plays the role of a buffer
+    my $reader= sub { #This is the actual reader routine
+	my $number=shift;
+	while($number>length($line)){ #get enough characters
+	    my $nextline=<$fh>;
+	    last unless $nextline;
+	    #I remove newlines. If not desired, comment the next line
+	    chomp($nextline);
+	    $line .= $nextline;
+	}
+	my $result=substr $line,0,$number;
+	(substr $line,0,$number)='';
+	return $result;
+    }
+}
+
+usage() unless @ARGV%2==0;
+usage() unless all {looks_like_number($ARGV[$_]) && $ARGV[$_]>=1}, map {2*$_+1} 0..(@ARGV-1)/2;
+my $res; # Don't print empty lines after file is consumed
+say $res while(@ARGV and $res=readN(shift @ARGV, shift @ARGV));
+sub usage {
+    say <<'END';
+    ./ch-1.pl file1 N1 file2 N2 ...
+    Reads N1 chars from file1, N2 from file2 and so on.
+    Filenames may repeat
+END
+}
diff --git a/challenge-098/wlmb/perl/ch-2.pl b/challenge-098/wlmb/perl/ch-2.pl
new file mode 100755
index 0000000000..1da3ea4401
--- /dev/null
+++ b/challenge-098/wlmb/perl/ch-2.pl
@@ -0,0 +1,15 @@
+#!/usr/bin/env perl
+# Perl weekly challenge 098
+# Task 2: Search Insert Position
+#
+# See https:/wlmb.github.io/2021/02/01/PWC098/#task-2-search-insert-position
+use warnings;
+use strict;
+use v5.12;
+use List::Util qw(uniq);
+use List::MoreUtils qw(first_index);
+
+my ($N, @N)=@ARGV;
+say "Input: \@N=(", join(", ", @N), ") and \$N=$N\n",
+    "Output: ",
+    first_index {$_==$N} sort {$a<=>$b} uniq (@N, $N);