Linked Lists again

1 files changed, 95 insertions, 0 deletions

diff --git a/challenge-071/simon-proctor/raku/ch-2.raku b/challenge-071/simon-proctor/raku/ch-2.raku
new file mode 100644
index 0000000000..ddb1154499
--- /dev/null
+++ b/challenge-071/simon-proctor/raku/ch-2.raku
@@ -0,0 +1,95 @@
+#!/usr/bin/env raku
+
+# Linked List Implementation modified from Challenge 68
+class ListNode {
+    has $.value;
+    has ListNode $!next;
+
+    method is-last() {
+        ! $!next.defined;
+    }
+
+    method next() {
+        $!next;
+    }
+    
+    method add-next( ListNode $next ) {
+         $!next = $next;
+    }
+
+    method remove-next() {
+        if ( $!next.is-last ) {
+            $!next = ListNode;
+        } else {
+            $!next = $!next.next;
+        }
+    }
+    
+    method move-node( ListNode $start, ListNode $node ) {
+        my $prev = $start;
+        my $next = $!next;
+        my $node-next = $node.next;
+        while $prev.next !~~ $node { $prev = $prev.next }
+        $!next = $node;
+        $node.add-next( $next );
+        $prev.add-next( $node-next );
+    }
+
+    method length( $count = 1 ) {
+        if self.is-last {
+            return $count;
+        } else {
+            return $!next.length( $count+1 );
+        }
+    }
+    
+    method gist() {
+        if self.is-last {
+            "$.value";
+        } else  {
+            "{$.value} -> {$!next.gist}";
+        }
+    }
+
+    method from-iterator( ListNode:U : @values ) {
+        my ( $start-node, $node );
+        
+        for @values -> $value {
+            if ! $start-node.defined {
+                $start-node = ListNode.new( :$value );
+                $node = $start-node;
+            } else {
+                my $next-node = ListNode.new( :$value );
+                $node.add-next( $next-node );
+                $node = $next-node;
+            }        
+        }
+        return $start-node;
+    }
+
+    method last-node() {
+        my $node = self;
+        while ! $node.is-last { $node = $node.next(); }
+        return $node;
+    }
+}
+
+sub MAIN (
+    UInt $N, #= Number from the end to remove if N is greated than list length remove the first item
+    *@list, #= List of values 
+) {
+    my $linked = ListNode.from-iterator(@list);
+    say "Before: {$linked.gist}";
+    if ( $N >= $linked.length ) {
+        $linked = $linked.next;
+    } else {
+        my $count = $linked.length - 1;
+        my $cur = $linked;
+        while ( $count > $N ) {
+            $count--;
+            $cur = $cur.next;
+        }
+        $cur.remove-next;
+    }
+    say "After: {$linked.gist}";
+}