Commit solutions for perl weekly challenge 027

2 files changed, 125 insertions, 0 deletions

diff --git a/challenge-027/duane-powell/perl5/ch-1.pl b/challenge-027/duane-powell/perl5/ch-1.pl
new file mode 100755
index 0000000000..7f04eda6b6
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+++ b/challenge-027/duane-powell/perl5/ch-1.pl
@@ -0,0 +1,62 @@
+#!/usr/bin/perl
+use Modern::Perl;
+use List::Util qw[min max];
+
+# Write a script to find the intersection of two straight lines. The co-ordinates of the two lines should be provided as command line parameter 
+
+usage() unless @ARGV == 8;
+my ($a,$b,$c,$d,$p,$q,$r,$s) = @ARGV;
+my ($x1,$y1,$z1,$x2,$y2,$z2);
+
+$x1 = $a-$c;
+$y1 = $d-$b;
+$z1 = ($x1 * $b) + ($y1 * $a);
+$x2 = $p-$r;
+$y2 = $s-$q;
+$z2 = ($x2 * $q) + ($y2 * $p);
+my $determinant =  ($x2*$y1) - ($x1*$y2);
+
+if ($determinant == 0) {
+	say "Line segments ($a,$b)($c,$d) and ($p,$q)($r,$s) are parallel";
+	exit;
+}
+my $x = ($x2 * $z1 - $x1 * $z2)/$determinant;
+my $y = ($y1 * $z2 - $y2 * $z1)/$determinant;
+my $intersect = ($x >= min($a,$c)) && ($x <= max($p,$r)) && ($y >= min($b,$d)) && ($y <= max($q,$s));
+
+if ($intersect) {
+	say "Intersection of line segments ($a,$b)($c,$d) and ($p,$q)($r,$s) is ($x,$y)";
+} else {	
+	say "Line segments ($a,$b)($c,$d) and ($p,$q)($r,$s) do not intersect";
+	say "Extended segment would intersect at ($x,$y)";
+}
+exit;
+
+sub usage {
+        print <<EOU;
+Usage:
+$0 a b c d  p q r s
+
+Calculate two line segments intersection point (x,y)
+Give 2 line segment end-points as a list of 8 numbers 
+
+Examples
+$0 -5 0 5 0     0 5 0 -5     # intersects at (0,0)
+$0 -5 6 5 6     0 5 0 -5     # does not intersect 
+$0 -5 6 5 6    -5 0 5  0     # parallel
+EOU
+        exit;
+}
+
+__END__
+
+./ch-1.pl -5 0 5 0     0 5 0 -5
+Intersection of line segments (-5,0)(5,0) and (0,5)(0,-5) is (0,0)
+
+./ch-1.pl -5 6 5 6     0 5 0 -5
+Line segments (-5,6)(5,6) and (0,5)(0,-5) do not intersect
+Extended segment would intersect at (0,6)
+
+./ch-1.pl -5 6 5 6    -5 0 5  0
+Line segments (-5,6)(5,6) and (-5,0)(5,0) are parallel
+
diff --git a/challenge-027/duane-powell/perl5/ch-2.pl b/challenge-027/duane-powell/perl5/ch-2.pl
new file mode 100755
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+++ b/challenge-027/duane-powell/perl5/ch-2.pl
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+#!/usr/bin/perl
+use Modern::Perl;
+
+# Write a script that allows you to capture/display historical data.
+
+my $h = Historical->new();
+sleep 1;
+$h->set(1);
+$h->get_history();
+sleep 1;
+$h->set(1);
+sleep 1;
+$h->set(11);
+sleep 1;
+$h->set(111);
+sleep 1;
+$h->set(11);
+sleep 1;
+$h->set(1);
+$h->get_history();
+exit;
+
+package Historical;
+sub new {
+	my $class = shift;
+	my $now = time;
+	my $self = {
+		x => 0,
+		x_history => {$now => 0},
+	};
+	return bless $self, $class;
+}
+sub set {
+	my $self = shift;
+	my $next = shift;
+	if ($self->{x} != $next) {
+		$self->{x} = $next;
+		my $now = time;
+		$self->{x_history}{$now} = $next;
+	}
+}
+sub get_history {
+	my $self = shift;
+	say "History of x is:";
+	foreach (sort (keys %{ $self->{x_history} })) {
+		say "$_ => ", $self->{x_history}{$_};
+	}
+}
+
+__END__
+
+./ch-2.pl 
+History of x is:
+1569256589 => 0
+1569256590 => 1
+History of x is:
+1569256589 => 0
+1569256590 => 1
+1569256592 => 11
+1569256593 => 111
+1569256594 => 11
+1569256595 => 1
+