Merge pull request #7394 from choroba/ech199

Add solutions to 199: Good Pairs & Good Triplets by E. Choroba

2 files changed, 49 insertions, 0 deletions

diff --git a/challenge-199/e-choroba/perl/ch-1.pl b/challenge-199/e-choroba/perl/ch-1.pl
new file mode 100755
index 0000000000..57a30da381
--- /dev/null
+++ b/challenge-199/e-choroba/perl/ch-1.pl
@@ -0,0 +1,21 @@
+#! /usr/bin/perl
+use warnings;
+use strict;
+use experimental qw{ signatures };
+
+use List::Util qw{ sum };
+
+sub good_pairs ($list) {
+    my %counts;
+    ++$counts{$_} for @$list;
+    return sum(map $_ * ($_ - 1) / 2, values %counts) // 0
+}
+
+use Test::More tests => 3 + 2;
+
+is good_pairs([1, 2, 3, 1, 1, 3]), 4, 'Example 1';
+is good_pairs([1, 2, 3]), 0, 'Example 2';
+is good_pairs([1, 1, 1, 1]), 6, 'Example 3';
+
+is good_pairs([1, 2, 1, 2, 1, 2, 1, 2, 1]), 16, '5+4';
+is good_pairs([]), 0, 'Empty';
diff --git a/challenge-199/e-choroba/perl/ch-2.pl b/challenge-199/e-choroba/perl/ch-2.pl
new file mode 100755
index 0000000000..c59cba3414
--- /dev/null
+++ b/challenge-199/e-choroba/perl/ch-2.pl
@@ -0,0 +1,28 @@
+#! /usr/bin/perl
+use warnings;
+use strict;
+use experimental 'signatures';
+
+sub good_triplets ($arr, $x, $y, $z) {
+    # Optimization: abs can't be < 0.
+    return 0 if grep $_ < 0, $x, $y, $z;
+
+    my $c = 0;
+    for my $i (0 .. $#$arr - 2) {
+        for my $j ($i + 1 .. $#$arr - 1) {
+            next unless abs($arr->[$i] - $arr->[$j]) <= $x;
+            for my $k ($j + 1 .. $#$arr) {
+                ++$c if abs($arr->[$j] - $arr->[$k]) <= $y
+                     && abs($arr->[$i] - $arr->[$k]) <= $z;
+            }
+        }
+    }
+    return $c
+}
+
+use Test::More tests => 2 + 1;
+
+is good_triplets([3, 0, 1, 1, 9, 7], 7, 2, 3), 4, 'Example 1';
+is good_triplets([1, 1, 2, 2, 3], 0, 0, 1), 0, 'Example 2';
+
+is good_triplets([map int rand 100, 1 .. 1000], 0, 0, -1), 0, 'Negative';