From 09354a370b75d7fc91c86d6b40b94866f9797569 Mon Sep 17 00:00:00 2001
From: Simon Proctor <simon.proctor@zoopla.co.uk>
Date: Wed, 15 Apr 2020 14:15:05 +0100
Subject: A bit OTT and it doen't pretty print but it's kinda cool and does the
 job

---
 challenge-056/simon-proctor/raku/ch-2.p6 | 130 +++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 challenge-056/simon-proctor/raku/ch-2.p6

diff --git a/challenge-056/simon-proctor/raku/ch-2.p6 b/challenge-056/simon-proctor/raku/ch-2.p6
new file mode 100644
index 0000000000..29475428b1
--- /dev/null
+++ b/challenge-056/simon-proctor/raku/ch-2.p6
@@ -0,0 +1,130 @@
+#!/usr/bin/env raku
+
+use v6;
+
+# BTree as string nodevalue[child1,child2]
+# Example tree 5(4(11(7)(2)))(8(13)(9(1)))
+
+grammar BTreeGrammar {
+    token TOP { <tree> };
+    token tree { <value> ["(" $<left>=<tree> ")"]? ["(" $<right>=<tree> ")"]? };
+    regex value { <-[()]>+ }
+}
+
+role BTree[::T] {
+    has T $.value is required;
+    has BTree[T] $.left;
+    has BTree[T] $.right;
+    
+    method Str( ) {
+        $!value ~ ( $!left ?? "({$!left.Str()})" !! "" ) ~ ( $!right ?? "({$!right.Str()})" !! "" );
+    }
+
+    method gist() {
+        self.Str();        
+    }
+
+    method traverse() {
+        gather {
+            if $!left {
+                for $!left.traverse -> @t {
+                    take ($!value, |@t);
+                }
+            }
+            if $!right {
+                for $!right.traverse -> @t {
+                    take ($!value, |@t);
+                }
+            }
+            if ! $!left && ! $!right {
+                take ( $!value, );
+            }
+        }
+    }
+
+    multi method from-Str('') { }
+    
+    multi method from-Str( ::?CLASS:U: Str $in ) {
+        my $match = BTreeGrammar.parse( $in );
+        if ( $match ) {
+            self.new(
+                value => $match<tree><value>.Str,
+                left => self.from-Str( $match<tree><left> ?? $match<tree><left>.Str !! '' ),
+                right => self.from-Str( $match<tree><right> ?? $match<tree><right>.Str !! '' )
+            );
+        } else {
+            die "Unable to Parse $in";
+        }
+            
+    }
+}
+
+class UBTree does BTree[UInt] {
+    submethod BUILD ( :$value, :$left = UBTree, :$right = UBTree ) {
+        $!value = $value.UInt();
+        $!left = $left;
+        $!right = $right;
+    }
+}
+
+#| Display the example Tree in Str and gist representations
+#| also displays all traversals
+multi sub MAIN ( 'example' ) {
+    my $example = example-tree;
+    say $example;
+    UBTree.from-Str( $example.Str ).say;
+    
+    for $example.traverse -> @row {
+        @row.join("->").say
+    }
+}
+
+#| Traverses the example tree and prints any routes that add up to the target.
+multi sub MAIN ( UInt $target, 'example' ) {
+    my $example = example-tree;
+
+    for $example.traverse -> @row {
+        @row.join("->").say if ( [+] @row ) == $target;
+    }
+}
+
+#| Given a target number and a tree string find all the traversals that add up to is
+#| Note the Tree string is in the format "number (left tree) (right tree)" spaces are optional
+multi sub MAIN ( UInt $target, *@rest ) {
+    my $tree = UBTree.from-Str( @rest.join("") );
+
+    for $tree.traverse -> @row {
+        @row.join("->").say if ( [+] @row ) == $target;
+    }
+}
+
+
+sub example-tree() {
+    return UBTree.new(
+        value => 5,
+        left => UBTree.new(
+            value => 4,
+            left => UBTree.new(
+                value => 11,
+                left => UBTree.new(
+                    value => 7,
+                ),
+                right => UBTree.new(
+                    value => 2,
+                )
+            )
+        ),
+        right => UBTree.new(
+            value => 8,
+            left => UBTree.new(
+                value => 13,
+            ),
+            right => UBTree.new(
+                value => 9,
+                right => UBTree.new(
+                    value => 1
+                )
+            )
+        )
+    );
+}
-- 
cgit