Merge pull request #2282 from ccntrq/challenge-078

Challenge 078

2 files changed, 71 insertions, 0 deletions

diff --git a/challenge-078/alexander-pankoff/perl/ch-1.pl b/challenge-078/alexander-pankoff/perl/ch-1.pl
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+++ b/challenge-078/alexander-pankoff/perl/ch-1.pl
@@ -0,0 +1,39 @@
+#!/usr/bin/env perl
+use v5.20;
+use utf8;
+use strict;
+use warnings;
+use autodie;
+use feature qw(say signatures);
+no warnings 'experimental::signatures';
+
+use List::Util qw(all reduce);
+
+# You are given an array @A containing distinct integers.
+#
+# Write a script to find all leader elements in the array @A. Print (0) if none
+# found.
+#
+# >> An element is leader if it is greater than all the elements to its right
+# >> side.
+
+my @A = @ARGV;
+
+my @leaders = find_leader_elements(@A);
+@leaders = (0) unless @leaders;
+
+say '(' . join( ', ', @leaders ) . ')';
+
+exit;
+
+sub find_leader_elements(@list) {
+    my $leaders = reduce {
+        my @leaders = @$a;
+        my $current = $b;
+
+        ( all { $current > $_ } @leaders ) ? [ $current, @leaders ] : $a
+    }
+    [], reverse @list;
+
+    return @{$leaders};
+}
diff --git a/challenge-078/alexander-pankoff/perl/ch-2.pl b/challenge-078/alexander-pankoff/perl/ch-2.pl
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+++ b/challenge-078/alexander-pankoff/perl/ch-2.pl
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+#!/usr/bin/env perl
+use v5.20;
+use utf8;
+use strict;
+use warnings;
+use autodie;
+use feature qw(say signatures);
+no warnings 'experimental::signatures';
+
+#  You are given array @A containing positive numbers and @B containing one or
+#  more indices from the array @A.
+#
+#  Write a script to left rotate @A so that the number at the first index of @B
+#  becomes the first element in the array. Similary, left rotate @A again so
+#  that the number at the second index of @B becomes the first element in the
+#  array.
+
+my @A = ( 10, 20, 30, 40, 50 );
+my @B = ( 3, 4 );
+
+for my $index (@B) {
+    say '[' . join( ', ', left_rotate( $index, @A ) ) . ']';
+}
+
+sub left_rotate ( $index, @array ) {
+    while ( $index-- ) {
+        my $top = shift @array;
+        push @array, $top;
+    }
+
+    return @array;
+}