PWC 002 solutions

2 files changed, 81 insertions, 0 deletions

diff --git a/challenge-002/bob-lied/perl/ch-1.pl b/challenge-002/bob-lied/perl/ch-1.pl
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+++ b/challenge-002/bob-lied/perl/ch-1.pl
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+#!/usr/bin/env perl
+# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
+#=============================================================================
+# ch-1.pl
+#=============================================================================
+# Copyright (c) 2021, Bob Lied
+#=============================================================================
+# Perl Weekly Challenge 002, Task #1, Remove Leading Zeroes
+# Write a script or one-liner to remove leading zeros from positive numbers.
+#=============================================================================
+
+use strict;
+use warnings;
+use 5.020;
+
+# Adding 0 forces interpretation as a number, loses leading zeroes
+for ( @ARGV ) { say $_+0; }
diff --git a/challenge-002/bob-lied/perl/ch-2.pl b/challenge-002/bob-lied/perl/ch-2.pl
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+++ b/challenge-002/bob-lied/perl/ch-2.pl
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+#!/usr/bin/env perl
+# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
+#=============================================================================
+# ch-2.pl
+#=============================================================================
+# Copyright (c) 2021, Bob Lied
+#=============================================================================
+# Perl Weekly Challenge 002, Task #2 Base 35
+# Write a script that can convert integers to and from a base35
+# representation, using the characters 0-9 and A-Y.
+#=============================================================================
+
+use strict;
+use warnings;
+use 5.020;
+
+use experimental qw/ signatures /;
+
+my $BASE = 35;
+
+my @BaseDigit = ( 0 .. 9, "A" .. "Z" );
+my %BaseVal;
+$BaseVal{$_} = $_ for 0..9;
+$BaseVal{$_} = 10 + ord($_) - ord("A") for "A" .. "Y";
+
+for ( @ARGV )
+{
+    if ( m/^\d+$/ )
+    {
+        say toBase($_, $BASE);
+    }
+    else
+    {
+        say fromBase($_, $BASE);
+    }
+}
+
+# Given a decimal number, represent in base 35.
+sub toBase($n, $base)
+{
+    my @answer;
+    while ( $n )
+    {
+        my $dig = $n % $base;
+        $n = ($n - $dig) / $base;
+        unshift @answer, $dig;
+    }
+
+    return join("", map { $BaseDigit[$_] } @answer);
+}
+
+sub fromBase($s, $base)
+{
+    my $place = $base;
+
+    my @digits = ( reverse split("", $s) );
+    my $val = $BaseVal{ shift @digits };
+    for my $dig ( @digits )
+    {
+        $val += $BaseVal{$dig} * $place;
+        $place *= $base;
+    }
+    return $val;
+}