Merge pull request #12679 from choroba/ech339

Add solutions to 339: Max Diff & Peak Point by E. Choroba

2 files changed, 82 insertions, 0 deletions

diff --git a/challenge-339/e-choroba/perl/ch-1.pl b/challenge-339/e-choroba/perl/ch-1.pl
new file mode 100755
index 0000000000..b649d93e38
--- /dev/null
+++ b/challenge-339/e-choroba/perl/ch-1.pl
@@ -0,0 +1,61 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use experimental qw( signatures );
+
+use constant RANDOM_TESTS => 50;
+
+sub max_diff_nested_loops(@ints) {
+    my $max_diff = 0;
+    for my $i (0 .. $#ints) {
+        for my $j (0 .. $#ints) {
+            next if $i == $j;
+
+            for my $k (0 .. $#ints) {
+                next if $i == $k || $j == $k;
+
+                for my $l (0 .. $#ints) {
+                    next if $i == $l || $j == $l || $k == $l;
+
+                    my $diff = $ints[$i] * $ints[$j] - $ints[$k] * $ints[$l];
+                    $max_diff = $diff if $diff > $max_diff;
+                }
+            }
+        }
+    }
+    return $max_diff
+}
+
+sub max_diff(@ints) {
+    @ints = sort { $a <=> $b } @ints;
+    return max_diff_nested_loops(@ints) if @ints <= 8;
+    return max_diff_nested_loops(@ints[0 .. 3, $#ints - 3 .. $#ints])
+}
+
+use Test::More tests => (5 + 1) * 2 + RANDOM_TESTS + 1;
+
+for my $max_diff (\&max_diff_nested_loops, \&max_diff) {
+    is $max_diff->(5, 9, 3, 4, 6), 42, 'Example 1';
+    is $max_diff->(1, -2, 3, -4), 10, 'Example 2';
+    is $max_diff->(-3, -1, -2, -4), 10, 'Example 3';
+    is $max_diff->(10, 2, 0, 5, 1), 50, 'Example 4';
+    is $max_diff->(7, 8, 9, 10, 10), 44, 'Example 5';
+    is $max_diff->(20, 17, -6, -8, -8, -3, -9, -1), 337, '6 not enough';
+}
+
+for (1 .. RANDOM_TESTS) {
+    my $size = 4 + int rand 10;
+    my @ints = map int(rand 50) - 25, 1 .. $size;
+    is max_diff(@ints), max_diff_nested_loops(@ints), "same @ints";
+
+}
+
+use Benchmark qw{ cmpthese };
+
+my @ints = map int(rand 50) - 25, 1 .. 25;
+is max_diff(@ints), max_diff_nested_loops(@ints), "same @ints";
+
+cmpthese(-3, {
+    nested    => sub { max_diff_nested_loops(@ints) },
+    optimised => sub { max_diff(@ints) },
+});
diff --git a/challenge-339/e-choroba/perl/ch-2.pl b/challenge-339/e-choroba/perl/ch-2.pl
new file mode 100755
index 0000000000..a89b957024
--- /dev/null
+++ b/challenge-339/e-choroba/perl/ch-2.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use experimental qw( signatures );
+
+sub peak_point(@gain) {
+    my $altitude = my $peak = 0;
+    for my $g (@gain) {
+        $altitude += $g;
+        $peak = $altitude if $altitude > $peak;
+    }
+    return $peak
+}
+
+use Test::More tests => 5;
+
+is peak_point(-5, 1, 5, -9, 2), 1, 'Example 1';
+is peak_point(10, 10, 10, -25), 30, 'Example 2';
+is peak_point(3, -4, 2, 5, -6, 1), 6, 'Example 3';
+is peak_point(-1, -2, -3, -4), 0, 'Example 4';
+is peak_point(-10, 15, 5), 10, 'Example 5';