Solutions to challenge-123

2 files changed, 105 insertions, 0 deletions

diff --git a/challenge-123/wanderdoc/perl/ch-1.pl b/challenge-123/wanderdoc/perl/ch-1.pl
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+++ b/challenge-123/wanderdoc/perl/ch-1.pl
@@ -0,0 +1,41 @@
+#!perl
+use strict;
+use warnings FATAL => qw(all);
+
+=prompt
+You are given an integer $n >= 1. Write a script to find the $nth element of Ugly Numbers.
+Ugly numbers are those number whose prime factors are 2, 3 or 5. For example, the first 10 Ugly Numbers are 1, 2, 3, 4, 5, 6, 8, 9, 10, 12.
+Example
+Input: $n = 7  Output: 8
+Input: $n = 10 Output: 12
+=cut
+
+
+
+
+
+
+
+use List::Util qw(min);
+
+my $N = shift or die "Number?$/";
+my $idx2 = my $idx3 = my $idx5 = 1;
+my @num;
+
+my $i = 1;
+
+$num[$i] = 1;
+
+while ( $i < $N )
+{
+     my $last = $num[$i];
+     $idx2++ while $num[$idx2] * 2 <= $last;
+     $idx3++ while $num[$idx3] * 3 <= $last;
+     $idx5++ while $num[$idx5] * 5 <= $last;
+     $i++;
+     $num[$i] = min($num[$idx2] * 2, $num[$idx3] * 3, $num[$idx5] * 5);
+    
+}
+
+
+print $num[$i], $/;
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diff --git a/challenge-123/wanderdoc/perl/ch-2.pl b/challenge-123/wanderdoc/perl/ch-2.pl
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+++ b/challenge-123/wanderdoc/perl/ch-2.pl
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+#!perl
+use strict;
+use warnings FATAL => qw(all);
+
+=prompt
+You are given coordinates of four points i.e. (x1, y1), (x2, y2), (x3, y3) and (x4, y4).
+Write a script to find out if the given four points form a square.
+=cut
+
+
+
+
+
+
+
+
+
+
+use Struct::Dumb;
+struct Point => [qw( x y )];
+
+sub check_square
+{
+     my @points = @_;
+     my %distances;
+
+     for my $i ( 0 .. 3 ) 
+     {
+          for my $j ( 1 .. 3 )
+          {
+               next if $i >= $j;
+               $distances{$i}{$j} = calc_distance(@points[$i, $j]);
+               return 0 if 0 == $distances{$i}{$j};
+          }
+     } 
+
+     return 1 
+     if
+
+
+     (
+          ($distances{0}{1} == $distances{0}{2} and $distances{0}{3} == 2 * $distances{0}{1} and $distances{0}{1} == $distances{2}{3})
+               or
+          ($distances{0}{1} == $distances{0}{3} and $distances{0}{2} == 2 * $distances{0}{1} and $distances{0}{1} == $distances{2}{3})
+               or
+          ($distances{1}{2} == $distances{1}{3} and $distances{0}{1} == 2 * $distances{1}{2} and $distances{1}{2} == $distances{0}{3})
+     );
+     return 0;
+
+}
+
+sub calc_distance # distance _squared_.
+{
+     my @pts = @_;
+     return   (($pts[0]->x - $pts[1]->x) * ($pts[0]->x - $pts[1]->x) + 
+               ($pts[0]->y - $pts[1]->y) * ($pts[0]->y - $pts[1]->y));
+}
+
+
+print check_square(Point(10, 20), Point(20, 20), Point(20, 10), Point(10, 10)), $/; # 1
+print check_square(Point(12, 24), Point(16, 10), Point(20, 12), Point(18, 16)), $/; # 0
+print check_square(Point(10, 30), Point(20, 10), Point(30, 40), Point(40, 20)), $/; # 1
+print check_square(Point(-2, -1), Point(-2,  2), Point( 1, -1), Point( 1,  2)), $/; # 1
+print check_square(Point(10, 10), Point(10, 20), Point(30, 10), Point(30, 20)), $/; # 0
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