added blog link and extended version of ch-2

1 files changed, 66 insertions, 0 deletions

diff --git a/challenge-092/james-smith/perl/ch-2-extended.pl b/challenge-092/james-smith/perl/ch-2-extended.pl
new file mode 100644
index 0000000000..8ea06c3e9f
--- /dev/null
+++ b/challenge-092/james-smith/perl/ch-2-extended.pl
@@ -0,0 +1,66 @@
+#!/usr/local/bin/perl
+
+use strict;
+
+use warnings;
+use feature qw(say);
+use Test::More;
+
+is_deeply( int_insert( [[2,6]], [[1,4], [8,10]]        ), [[1,6],[8,10]] );  ## Simple overlap
+is_deeply( int_insert( [[2,6]], [[1,7], [8,10]]        ), [[1,7],[8,10]] );  ## New entry entirely in one region
+is_deeply( int_insert( [[1,7]], [[2,6], [8,10]]        ), [[1,7],[8,10]] );  ## New entry engulfs one region
+is_deeply( int_insert( [[1,7]], [[2,3], [4,5], [8,10]] ), [[1,7],[8,10]] );  ## New entry engulfs 2 regions
+is_deeply( int_insert( [[2,8]], [[1,2], [3,4]], [[5,6], [7,9]] ), [[1,9]] );   ## Merges multiple regions
+is_deeply( int_insert( [[5,8]], [[1,2], [3,7], [8,10]] ), [[1,2],[3,10]] );  ## Merges two groups
+is_deeply( int_insert( [[10,11]], [[1,5],[7,9]]        ), [[1,5],[7,9],[10,11]] ); ## New entry at end
+is_deeply( int_insert( [[5,6]], [[1,2],[7,9]]          ), [[1,2],[5,6],[7,9]] );   ## New entry in middle
+is_deeply( int_insert( [[1,2]], [[5,6],[7,9]]          ), [[1,2],[5,6],[7,9]] );   ## New entry at start
+is_deeply( int_insert( [[1,1e7]], [map { [2*$_,2*$_+1] } 1..4_999_999] ), [[1,1e7]] ); ## Check it isn't really slow!
+
+
+
+done_testing( );
+
+use Data::Dumper qw(Dumper);
+
+sub int_insert {
+  my ($result,@rest) = @_;
+  my @a = @{$result};
+  foreach (@rest) {
+    my @b = @{$_};
+    my @new;
+    while( @a && @b ) {
+      if( $a[0][1] < $b[0][0] ) {
+        push @new, shift @a;
+        next;
+      }
+      if( $b[0][1] < $a[0][0] ) {
+        push @new, shift @b;
+        next;
+      }
+      ## We have an overlap;
+      my $new_region = shift @a;
+      $new_region->[0] = $b[0][0] if $new_region->[0] > $b[0][0];
+      $new_region->[1] = $b[0][1] if $new_region->[1] < $b[0][1];
+      shift @b; ## New region is the overlap of the two regions
+      while( @a || @b ) {
+        if( @a && $a[0][0] <= $new_region->[1] ) {
+          $new_region->[1] = $a[0][1] if $new_region->[1] < $a[0][1];
+          shift @a;
+          next;
+        }
+        if( @b && $b[0][0] <= $new_region->[1] ) {
+          $new_region->[1] = $b[0][1] if $new_region->[1] < $b[0][1];
+          shift @b;
+          next;
+        }
+        last;
+      }
+      push @new, $new_region;
+    }
+    push @new, @a, @b;
+    @a = @new;
+  }
+  return \@a;
+}
+