Week 191 Task 1 boblied

2 files changed, 71 insertions, 2 deletions

diff --git a/challenge-191/bob-lied/README b/challenge-191/bob-lied/README
index c231e3a589..6fb0b491da 100644
--- a/challenge-191/bob-lied/README
+++ b/challenge-191/bob-lied/README
@@ -1,3 +1,3 @@
-Solutions to weekly challenge 138 by Bob Lied
+Solutions to weekly challenge 191 by Bob Lied
 
-https://perlweeklychallenge.org/blog/perl-weekly-challenge-138/
+https://perlweeklychallenge.org/blog/perl-weekly-challenge-191/
diff --git a/challenge-191/bob-lied/perl/ch-1.pl b/challenge-191/bob-lied/perl/ch-1.pl
new file mode 100644
index 0000000000..cdc0d034a1
--- /dev/null
+++ b/challenge-191/bob-lied/perl/ch-1.pl
@@ -0,0 +1,69 @@
+#!/usr/bin/env perl
+# vim:set ts=4 sw=4 sts=4 et ai wm=0 nu:
+#=============================================================================
+# ch-1.pl Perl Weekly Challenge Task 1 Twice Largest
+#=============================================================================
+# Copyright (c) 2023, Bob Lied
+#=============================================================================
+# You are given list of integers, @list.
+# Write a script to find out whether the largest item in the list is at least
+# twice as large as each of the other items.
+# 
+# Example 1 Input: @list = (1,2,3,4) Output: -1
+#   The largest in the given list is 4.  #   However 4 is not greater than 2*3
+# Example 2 Input: @list = (1,2,0,5) Output: 1
+#   The largest in the given list is 5. Also 5 is greater than twice of
+#   every remaining elements.
+# Example 3 Input: @list = (2,6,3,1) Output: 1
+#   The largest in the given list is 6. Also 6 is greater than twice of
+#   every remaining elements.
+# Example 4 Input: @list = (4,5,2,3) Output: -1
+#   The largest in the given list is 5. But 5 is less than 2*4 and 2*3
+#
+# Specification is ambiguous about multiple occurrences of the max.  One
+# interpretation is that only one copy of max is taken out of the list for
+# comparison, meaning that the duplicate will fail the test.  The other
+# interpretation is that all copies of the maximum value are taken out
+# of the list before comparison.
+#=============================================================================
+
+use v5.36;
+
+use List::Util qw/all/;
+use List::MoreUtils qw/after_incl/;
+
+use Getopt::Long;
+my $Verbose = 0;
+my $DoTest  = 0;
+
+GetOptions("test" => \$DoTest, "verbose" => \$Verbose);
+exit(!runTest()) if $DoTest;
+
+(my $list = "@ARGV") =~ s/[[:punct:]]/ /g;
+say twiceLargest( [ split ' ', $list ] );
+
+sub twiceLargest($list)
+{
+    # Sort to put the max at the front, then shift it off
+    my @rest = sort { $b <=> $a } $list->@*;
+    my $max = shift @rest;
+
+    # Handle duplicates of max by excluding all max values.
+    @rest = after_incl { $_ < $max } @rest;
+
+    return ( all { $max >= 2*$_ } @rest )? 1 : -1;
+}
+
+sub runTest
+{
+    use Test2::V0;
+
+    is( twiceLargest( [1,2,3,4]), -1, "Example 1");
+    is( twiceLargest( [1,2,0,5]),  1, "Example 2");
+    is( twiceLargest( [2,6,3,1]),  1, "Example 3");
+    is( twiceLargest( [4,5,2,3]), -1, "Example 4");
+    is( twiceLargest( [8,8,2,3]),  1, "Dup max");
+
+    done_testing;
+}
+