Create ch-2.pl

1 files changed, 40 insertions, 0 deletions

diff --git a/challenge-197/james-smith/perl/ch-2.pl b/challenge-197/james-smith/perl/ch-2.pl
new file mode 100644
index 0000000000..b16ae1d52e
--- /dev/null
+++ b/challenge-197/james-smith/perl/ch-2.pl
@@ -0,0 +1,40 @@
+#!/usr/local/bin/perl
+
+use strict;
+use warnings;
+use feature qw(say);
+use Test::More;
+
+my @TESTS = (
+  [ [1,1,2],       1 ],
+  [ [2,1,2],       0 ],
+  [ [1,1,1,2],     0 ],
+  [ [1,2,1,3,1,5], 1 ],
+  [ [1,2,1,3,1],   1 ],
+  [ [1,2],         1 ],
+  [ [2,1],         1 ],
+  [ [1],           1 ],
+  [ [1,5,1,1,6,4], 1 ],
+  [ [1,3,2,2,3,1], 1 ],
+  [ [2,3,1,3,1,2,1], 1 ],
+);
+
+
+is( check( wiggle_sort(@{$_->[0]}) ), $_->[1] ) for @TESTS;
+done_testing();
+
+sub wiggle_sort {
+  return @_ if @_<2;
+  @_ = sort { $a <=> $b } @_;
+  my @q = splice @_,(@_+1)/2;
+  return if @q < @_ && $_[1]==$q[0];
+  return map { @q ? ( $_ == $q[0] ? (return) : $_,shift @q ) : $_ } @_;
+}
+
+sub check {
+  return 0 unless @_;
+  my($t,$d) = (shift,1);
+  ($_<=>$t)!=$d?return 0:($t=$_,$d*=-1) for @_;
+  return 1;
+}
+