Week 205 submission

3 files changed, 120 insertions, 0 deletions

diff --git a/challenge-205/peter-campbell-smith/blog.txt b/challenge-205/peter-campbell-smith/blog.txt
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+++ b/challenge-205/peter-campbell-smith/blog.txt
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+http://ccgi.campbellsmiths.force9.co.uk/challenge/205
diff --git a/challenge-205/peter-campbell-smith/perl/ch-1.pl b/challenge-205/peter-campbell-smith/perl/ch-1.pl
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+++ b/challenge-205/peter-campbell-smith/perl/ch-1.pl
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+#!/usr/bin/perl
+
+# Peter Campbell Smith - 2023-02-20
+
+use v5.28;
+use utf8;
+use warnings;
+use List::Uniq ':all';
+
+# Task: You are given an array of integers. Write a script to find the 
+# third highest value in the array.
+
+# Blog: http://ccgi.campbellsmiths.force9.co.uk/challenge/205/1
+
+my (@test, $j);
+
+third_highest(5, 3, 4);
+third_highest(5, 6);
+third_highest(5, 4, 4, 3);
+third_highest(-3, -2, -1);
+third_highest(1, 1, 1, 1, 1);
+third_highest();
+
+# make a longer example - 100 random numbers in (0 .. 999)
+for $j (0 .. 99) {
+	$test[$j] = int(rand(1000));
+}
+third_highest(@test);
+
+sub third_highest {
+	
+	# find the 3rd highest value in the argument list
+	my (@array, $result, $count);
+	
+	# get the unique values in the list and sort them largest to smallest
+	@array = sort {$b <=> $a} uniq(@_);
+	$count = scalar @array;
+	
+	# select appropriate legend
+	if ($count >= 3) {
+		$result = qq[First highest is $array[0]. Second highest is $array[1]. Third highest is $array[2].];
+	} elsif ($count == 2) {
+		$result = qq[First highest is $array[0]. Second highest is $array[1]. Third highest is missing so maximum is returned.];
+	} elsif ($count == 1) {
+		$result = qq[First highest is $array[0]. Second and third highest are missing so maximum is returned.];
+	} else {
+		$result = 'List is empty.';
+	}
+
+	say qq[\nInput:  \@array = (] . join (', ', @_) . ')' . qq[\nOutput: $result];
+}
+
+	
+
diff --git a/challenge-205/peter-campbell-smith/perl/ch-2.pl b/challenge-205/peter-campbell-smith/perl/ch-2.pl
new file mode 100755
index 0000000000..8a9db793b0
--- /dev/null
+++ b/challenge-205/peter-campbell-smith/perl/ch-2.pl
@@ -0,0 +1,65 @@
+#!/usr/bin/perl
+
+# Peter Campbell Smith - 2023-02-20
+
+use v5.28;
+use utf8;
+use warnings;
+use List::Uniq ':all';
+
+# Task: You are given an array of integers. Write a script to find the highest value obtained 
+# by XORing any two distinct members of the array.
+
+# Blog: http://ccgi.campbellsmiths.force9.co.uk/challenge/205/2
+
+my ($j, @test);
+
+max_xor(1, 2, 3, 4, 5, 6, 7);
+max_xor(2, 4, 1, 3);
+max_xor(10, 5, 7, 12, 8);
+max_xor(21, 25);
+max_xor(32, 32, 32, 32);
+
+for $j (1 .. 20) {
+	@test[$j - 1] = int(rand(126)) + 1;
+}
+max_xor(@test);
+
+sub max_xor {
+	
+	my ($count, $i, $j, $max, $xor, $result, @array, $largest, $limit);
+	
+	@array = @_;
+	$count = scalar @array;
+
+	# find the largest number in the array
+	$largest = 0;
+	for $j (@array) {
+		$largest = $j if $j > $largest;
+	}
+	
+	# find the largest possible xor
+	for $j (1 .. 31) {
+		next unless 2 ** $j > $largest;
+		$limit = 2 ** $j - 1;
+		last;
+	}
+
+	# now scan for the largest xor
+	$max = -1;
+	if ($count >= 2) {
+		SCAN: for $i (0 .. $count - 2) {
+			for $j ($i + 1 .. $count - 1) {
+				$xor = $_[$i] ^ $_[$j];
+				if ($xor > $max) {
+					$result = qq[$array[$i] xor $array[$j] = $xor];
+					$max = $xor;
+					last SCAN if $max == $limit;
+				}
+			}
+		}
+		say qq[\nInput:  \@array = (] . join(', ', @_) . ')' . qq[\nOutput: $result];
+	} else {
+		say 'Array must contan at least 2 elements.'
+	}
+}