solution 2...

2 files changed, 64 insertions, 0 deletions

diff --git a/challenge-123/james-smith/perl/ch-1.pl b/challenge-123/james-smith/perl/ch-1.pl
new file mode 100644
index 0000000000..2348c8b946
--- /dev/null
+++ b/challenge-123/james-smith/perl/ch-1.pl
@@ -0,0 +1,22 @@
+#!/usr/local/bin/perl
+
+use strict;
+
+use warnings;
+use feature qw(say);
+use Test::More;
+use Benchmark qw(cmpthese timethis);
+use Data::Dumper qw(Dumper);
+
+my @TESTS = (
+  [ 0, 1 ],
+);
+
+is( my_function($_->[0]), $_->[1] ) foreach @TESTS;
+
+done_testing();
+
+sub my_function {
+  return 1;
+}
+
diff --git a/challenge-123/james-smith/perl/ch-2.pl b/challenge-123/james-smith/perl/ch-2.pl
new file mode 100644
index 0000000000..af4005104e
--- /dev/null
+++ b/challenge-123/james-smith/perl/ch-2.pl
@@ -0,0 +1,42 @@
+#!/usr/local/bin/perl
+
+use strict;
+
+use warnings;
+use feature qw(say);
+use Test::More;
+use Benchmark qw(cmpthese timethis);
+use Data::Dumper qw(Dumper);
+
+my @TESTS = (
+  [ [ [10,20],[20,20],[20,10],[10,10] ], 1 ],
+  [ [ [12,24],[16,10],[20,12],[18,16] ], 0 ],
+);
+
+is( is_square(@{$_->[0]}), $_->[1] ) foreach @TESTS;
+
+done_testing();
+
+sub is_square {
+  my @pts = @_;
+
+  ## If we measure the squared distances between each
+  ## pari of points of a square we get two distances -
+  ## the edge and diagonal.
+  ## The latter being twice the former...
+  ##
+  ## No other combination of points has this property.
+
+  ## Compute distances...
+  my %D;
+  while(@pts>1) {
+    my $a = shift @pts;
+    $D{($a->[0]-$_->[0])**2+($a->[1]-$_->[1])**2}++ foreach @pts;
+  }
+  my @K = keys %D;
+  return 0 unless @K== 2;      ## More than two distances
+  return 1 if $K[0]*2==$K[1];  ## First no is the diagonal
+  return 1 if $K[1]*2==$K[0];  ## First no is the edge..
+  return 0;                    ## Equilat triangles..
+}
+