Merge pull request #2294 from jacoby/master

challenge 78

2 files changed, 99 insertions, 0 deletions

diff --git a/challenge-078/dave-jacoby/perl/ch-1.pl b/challenge-078/dave-jacoby/perl/ch-1.pl
new file mode 100755
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+++ b/challenge-078/dave-jacoby/perl/ch-1.pl
@@ -0,0 +1,45 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw{ say signatures state };
+no warnings qw{ experimental };
+
+use List::Util qw{ max };
+
+# 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.
+
+# Input: @A = (9, 10, 7, 5, 6, 1)
+# Output: (10, 7, 6, 1)
+
+my @A;
+@A = ( 9, 10, 7, 5, 6, 1 );
+my @o1 = leader_element(@A);
+say join ', ', @A;
+say join ', ', @o1;
+say '';
+
+# Input: @A = (3, 4, 5)
+# Output: (5)
+
+@A = ( 3, 4, 5 );
+my @o2 = leader_element(@A);
+say join ', ', @A;
+say join ', ', @o2;
+say '';
+
+sub leader_element ( @arr ) {
+    my @output;
+
+    while (@arr) {
+        my $max = max @arr;
+        push @output, $arr[0] if $max == $arr[0];
+        shift @arr;
+    }
+
+    push @output, 0 unless scalar @output;
+    return wantarray ? @output : \@output;
+}
diff --git a/challenge-078/dave-jacoby/perl/ch-2.pl b/challenge-078/dave-jacoby/perl/ch-2.pl
new file mode 100755
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+++ b/challenge-078/dave-jacoby/perl/ch-2.pl
@@ -0,0 +1,54 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature qw{ say signatures state };
+no warnings qw{ experimental };
+
+# 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.
+
+#       and this is where you look into the examples to tell,
+#       because by description, I would've thought that you
+#       work again on the modified array, not starting over
+
+my $o1 = left_rotation( [ 10, 20, 30, 40, 50 ], [ 3, 4 ] );
+my $o2 = left_rotation( [ 7, 4, 2, 6, 3 ], [ 1, 3, 4 ] );
+
+for my $o ( $o1, $o2 ) {
+    for my $r ( $o->@* ) {
+        print '[';
+        print join ' ', $r->@*;
+        say ']';
+    }
+    say '';
+}
+
+# Example 1
+# [40 50 10 20 30]
+# [50 10 20 30 40]
+
+# Example 2
+# [4 2 6 3 7]
+# [6 3 7 4 2]
+# [3 7 4 2 6]
+
+sub left_rotation ( $nums, $indices ) {
+    my @output;
+    for my $i ( $indices->@* ) {
+        my @new = $nums->@*;
+        for ( 1 .. $i ) {
+            push @new, shift @new;
+        }
+        push @output, [@new];
+    }
+
+    push @output, 0 unless scalar @output;
+    return wantarray ? @output : \@output;
+}