pushing solns to 93....

4 files changed, 130 insertions, 0 deletions

diff --git a/challenge-093/james-smith/blog.txt b/challenge-093/james-smith/blog.txt
new file mode 100644
index 0000000000..632a590f10
--- /dev/null
+++ b/challenge-093/james-smith/blog.txt
@@ -0,0 +1 @@
+http://blogs.perl.org/users/james_curtis-smith/2020/12/perl-weekly-challenge-93.html
diff --git a/challenge-093/james-smith/perl/ch-1-gcd.pl b/challenge-093/james-smith/perl/ch-1-gcd.pl
new file mode 100644
index 0000000000..632f185f5a
--- /dev/null
+++ b/challenge-093/james-smith/perl/ch-1-gcd.pl
@@ -0,0 +1,58 @@
+#!/usr/local/bin/perl
+
+use strict;
+
+use warnings;
+use feature qw(say);
+use Test::More;
+
+## We represent the tree as a nested array.
+## Each "tree" is an arrayref with up to 3 values
+##   * value of node {scalar}
+##   * left sub-tree {arrayref}
+##   * right sub-tree {arrayref}
+## note we don't have a right sub-tree without a left subtree.
+is( most_points_in_line( [1,1],[2,2],[3,3]             ), 3 );
+is( most_points_in_line( [1,1],[2,2],[3,1],[1,3],[5,3] ), 3 );
+
+done_testing( );
+
+use Data::Dumper qw(Dumper);
+
+sub most_points_in_line {
+  my @nodes = @_;
+  my %lines;
+  foreach my $i (0..(@nodes-2)) {
+    foreach my $j (($i+1)..(@nodes-1)) {
+      my $dir = '-';
+      my( $dx,$dy) = ( $nodes[$i][0]-$nodes[$j][0], $nodes[$i][1]-$nodes[$j][1] );
+      if( $dx && $dy ) {
+        my $gcd = gcd( $dx,$dy );
+        $dir = $dx/$gcd.'-'.$dy/$gcd;
+      } else {
+        $dir = $dx ? '-' : '|';
+      }
+      $lines{$i.':'.$dir}++;
+      $lines{$j.':'.$dir}++;
+    }
+  }
+  my $max = 0;
+  foreach (values %lines) {
+    $max = $_ if $_ > $max;
+  }
+  return $max+1;
+}
+
+
+sub gcd {
+  my( $n,$m,$s ) = (@_,1);
+  ($n,$m) = (-$n,-$m) if $n < 0;
+  if( $m < 0 ) {
+    $s = -1;
+    $m = -$m;
+  }
+  ($n,$m) = ($m,$n) if $m>$n;
+  ($n,$m) = ( $m, $n % $m ) while $n % $m;
+  return $m*$s;
+}
+
diff --git a/challenge-093/james-smith/perl/ch-1.pl b/challenge-093/james-smith/perl/ch-1.pl
new file mode 100644
index 0000000000..0db2bbc574
--- /dev/null
+++ b/challenge-093/james-smith/perl/ch-1.pl
@@ -0,0 +1,40 @@
+#!/usr/local/bin/perl
+
+use strict;
+
+use warnings;
+use feature qw(say);
+use Test::More;
+
+## We represent the tree as a nested array.
+## Each "tree" is an arrayref with up to 3 values
+##   * value of node {scalar}
+##   * left sub-tree {arrayref}
+##   * right sub-tree {arrayref}
+## note we don't have a right sub-tree without a left subtree.
+is( most_points_in_line( [1,1],[2,2],[3,3]             ), 3 );
+is( most_points_in_line( [1,1],[2,2],[3,1],[1,3],[5,3] ), 3 );
+
+done_testing( );
+
+use Data::Dumper qw(Dumper);
+
+sub most_points_in_line {
+  my @nodes = @_;
+  my %lines;
+  foreach my $i (0..(@nodes-2)) {
+    foreach my $j (($i+1)..(@nodes-1)) {
+      my $dir = $nodes[$i][1] == $nodes[$j][1]
+              ? '-'
+              :  ($nodes[$i][0]-$nodes[$j][0])/($nodes[$i][1]-$nodes[$j][1]);
+      $lines{$i.':'.$dir}++;
+      $lines{$j.':'.$dir}++;
+    }
+  }
+  my $max = 0;
+  foreach (values %lines) {
+    $max = $_ if $_ > $max;
+  }
+  return $max+1;
+}
+
diff --git a/challenge-093/james-smith/perl/ch-2.pl b/challenge-093/james-smith/perl/ch-2.pl
new file mode 100644
index 0000000000..5f50e6bec8
--- /dev/null
+++ b/challenge-093/james-smith/perl/ch-2.pl
@@ -0,0 +1,31 @@
+#!/usr/local/bin/perl
+
+use strict;
+
+use warnings;
+use feature qw(say);
+use Test::More;
+
+## We represent the tree as a nested array.
+## Each "tree" is an arrayref with up to 3 values
+##   * value of node {scalar}
+##   * left sub-tree {arrayref}
+##   * right sub-tree {arrayref}
+## note we don't have a right sub-tree without a left subtree.
+is( tree_sum( [1,[2,[3],[4]]] ), 13 );
+is( tree_sum( [1,[2,[4]],[3,[5],[6]]] ), 26 );
+
+done_testing( );
+
+use Data::Dumper qw(Dumper);
+
+sub tree_sum {
+  my ( $node,$sum ) = @_;
+  $sum||=0;
+  return $node->[0] + $sum if @{$node} < 2; ## We have a leaf so return the sum...
+  ## We have a branch - so return the sum foreach branch. for reach branch we need to add
+  ## the current value to the sum from ancestors...
+  return tree_sum( $node->[1], $node->[0] + $sum ) +
+         ( @{$node} == 3 ? tree_sum( $node->[2], $node->[0] + $sum ) : 0 );
+}
+