From ba8de7fe4400e70c45c144d2110f22ba811993ea Mon Sep 17 00:00:00 2001
From: E7-87-83 <fungcheokyin@gmail.com>
Date: Fri, 13 Aug 2021 21:48:41 +0800
Subject: 1st commit of Task 2

---
 challenge-125/cheok-yin-fung/perl/ch-2.pl | 113 ++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 challenge-125/cheok-yin-fung/perl/ch-2.pl

diff --git a/challenge-125/cheok-yin-fung/perl/ch-2.pl b/challenge-125/cheok-yin-fung/perl/ch-2.pl
new file mode 100644
index 0000000000..83851812d8
--- /dev/null
+++ b/challenge-125/cheok-yin-fung/perl/ch-2.pl
@@ -0,0 +1,113 @@
+#!/usr/bin/perl
+# The Weekly Challenge 094
+# Task 2: Binary Tree Diameter
+use strict;
+use warnings;
+use v5.10.0;
+use experimental 'signatures';
+use List::Util qw/max/;
+use Test::More tests => 3;
+
+# begin: code from Week 113
+
+die <<FOO
+Incorrect input format.
+Usage: ch-2.pl [binary tree in array format, \'x\' for null nodes]
+for example, \$ ch-2.pl 2 3 5 x 7
+    2 
+   / \\
+  3   5
+   \\
+    7
+FOO
+    unless defined($ARGV[0]) && consistency(@ARGV);
+# end: code from Week 113
+
+my @tree_argv = map { $_ eq 'x' ? undef : $_ } @ARGV;
+say "Diameter: ", diameter(\@tree_argv);
+say "";
+
+
+sub diameter {
+    my @tree = $_[0]->@*;
+    return 0 if scalar @tree == 1;
+    my @leaf_id = collect_leaves_by_id(\@tree)->@*;
+    my $max_dist = max map {depth($tree[$_])} @leaf_id;
+    for my $i (0..$#leaf_id-1) {
+        for my $j ($i+1..$#leaf_id) {
+            my $dist = path_distance(\@tree, $leaf_id[$i], $leaf_id[$j]);
+            $max_dist = $dist if $dist > $max_dist;
+        }
+    }
+    return $max_dist;
+}
+
+sub collect_leaves_by_id {
+    my @tree = $_[0]->@*;
+    my @leaves;
+    for my $node_id (0..$#tree) {
+        if (defined($tree[$node_id])) {
+            push @leaves, $node_id 
+              if !defined($tree[$node_id*2+1]) && !defined($tree[$node_id*2+2]);
+        }
+    }
+    return [@leaves];
+}
+
+sub path_distance {
+    my @tree = $_[0]->@*;
+    my ($i1, $i2) = ($_[1], $_[2]);
+    return 0 if $i1 == $i2;
+    if (defined($tree[$i1]) && defined($tree[$i2])) {
+        my $n1 = $i1 < $i2 ? $i1 : $i2;
+        my $n2 = $i1 < $i2 ? $i2 : $i1;
+        my $d1 = depth($n1);
+        my $d2 = depth($n2);
+        my $u1 = $n1;
+        my $u2 = $n2;
+        my $depth_diff = $d2-$d1;
+        for (1..$depth_diff) {
+            $u2 = int (($u2-1) / 2);
+        }
+
+        while ($u1!=$u2) {
+            $u1 = int (($u1-1) / 2);
+            $u2 = int (($u2-1) / 2);
+        }
+        my $d_common = depth($u1);
+        return $d1+$d2-2*$d_common; 
+    }
+    else {
+        return -1;
+    }
+}
+
+sub depth ($n) {
+    return int (log($n+1) / log 2);
+}
+
+
+ok diameter([2, 3, 5, undef, 7]) == 3, "Tree in Week 113";
+ok diameter([1, 2, 5, 3, 4, 6, 7, (undef) x 6, 8, 10, (undef) x 12, 9 ]) == 6,
+     "Tree in Example provided";
+ok diameter([0..30]) == 8, "a Complete Binary Tree";
+
+
+# ======== BEGIN: code from Week 113 ===============
+
+sub consistency {
+    my @t = @_;
+    return 0 if !defined($t[0]) || ($t[0] !~ /^\d+$/ && $t[0] ne 'x');
+    for my $ind (1..$#t) { 
+        if ($t[$ind] =~ /^\d+$/) {
+            if ($t[($ind-1)/2] eq 'x') {
+                return 0;
+            }
+        } 
+        elsif ($t[$ind] ne 'x') {
+            return 0;
+        }
+    }
+    return 1;
+}
+# ========== END: code from Week 113 ===============
-- 
cgit 


From 85d81a12be37eba47cbad2cb4f8218d951436bec Mon Sep 17 00:00:00 2001
From: E7-87-83 <fungcheokyin@gmail.com>
Date: Fri, 13 Aug 2021 22:40:21 +0800
Subject: week 125

---
 challenge-125/cheok-yin-fung/perl/ch-1.pl | 57 +++++++++++++++++++++++++++++++
 challenge-125/cheok-yin-fung/perl/ch-2.pl |  5 ++-
 2 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 challenge-125/cheok-yin-fung/perl/ch-1.pl

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;
-- 
cgit