week 125

2 files changed, 61 insertions, 1 deletions

diff --git a/challenge-125/cheok-yin-fung/perl/ch-1.pl b/challenge-125/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..10fabf76ef
--- /dev/null
+++ b/challenge-125/cheok-yin-fung/perl/ch-1.pl
@@ -0,0 +1,57 @@
+#!/usr/bin/perl
+# The Weekly Challenge 125
+# Task 1: Pythagorean Triples
+# Usage: ch-1.pl $n
+use strict;
+use warnings;
+use v5.10.0;
+use experimental 'signatures';
+use List::Util qw/max/;
+use Test::More tests => 7;
+
+my $num = $ARGV[0] || 5;
+my @arr = pyth($num)->@*;
+
+if (scalar @arr > 0) {
+    say "(",join(", ", $_->@*),")" foreach(@arr);
+}
+else {
+    say "-1";
+}
+
+
+
+sub pyth ($n) {
+    my @ans;
+    for my $a (1..int $n/sqrt(2) ) {
+        my $is_sq = $n*$n-$a*$a;
+        if (sqrt($is_sq) == int sqrt($is_sq)) {
+            push @ans, [$a, sqrt($is_sq), $n];
+        }
+    }
+
+    for my $a0 (1..$n-1) {
+        my $is_sq = $a0*$a0 + $n*$n;
+        if (sqrt($is_sq) == int sqrt($is_sq)) {
+            push @ans, [$a0, $n, sqrt($is_sq)];
+        }
+    }
+
+    for my $b0 ($n+1..$n*$n) {
+        my $is_sq = $b0*$b0 + $n*$n;
+        if (sqrt($is_sq) == int sqrt($is_sq)) {
+            push @ans, [$n , $b0 ,sqrt($is_sq)];
+        }
+    }
+
+    return \@ans;
+}
+
+
+ok scalar @{pyth(1)} == 0, "Number 1";
+ok scalar @{pyth(2)} == 0, "Number 2";
+ok scalar @{pyth(3)} == 1, "Number 3";
+ok scalar @{pyth(4)} == 1, "Number 4";
+ok scalar @{pyth(5)} == 2, "Number 5";
+ok scalar @{pyth(8)} == 2, "Number 8";
+ok scalar @{pyth(13)} == 2, "Number 13";
diff --git a/challenge-125/cheok-yin-fung/perl/ch-2.pl b/challenge-125/cheok-yin-fung/perl/ch-2.pl
index 83851812d8..91ca281ea0 100644
--- a/challenge-125/cheok-yin-fung/perl/ch-2.pl
+++ b/challenge-125/cheok-yin-fung/perl/ch-2.pl
@@ -1,6 +1,7 @@
 #!/usr/bin/perl
-# The Weekly Challenge 094
+# The Weekly Challenge 125
 # Task 2: Binary Tree Diameter
+# Usage: ch-2.pl [binary tree in array format, 'x' for null nodes]
 use strict;
 use warnings;
 use v5.10.0;
@@ -42,6 +43,8 @@ sub diameter {
     return $max_dist;
 }
 
+# above: I am tired this week therefore I don't optimize. -- CY
+
 sub collect_leaves_by_id {
     my @tree = $_[0]->@*;
     my @leaves;