Add some algo

1 files changed, 33 insertions, 0 deletions

diff --git a/src/quick-union.lisp b/src/quick-union.lisp
new file mode 100644
index 0000000..ca61703
--- /dev/null
+++ b/src/quick-union.lisp
@@ -0,0 +1,33 @@
+;; Create network nodes
+(defun create-network (n)
+  "Build a quick-find network using a dynamic vector"
+  (let ((nodes (make-array n :fill-pointer 0)))
+    (dotimes (id n)
+      (vector-push id nodes))
+    nodes))
+
+;; Find the root of a node
+(defun find-root (network node)
+  "Find the root of a sub-tree in the network."
+  (do ((id node value)
+       (value (elt network node) (elt network value)))
+      ((= id value) id)))
+
+;; Check if two nodes are connected
+(defmacro connected (network n1 n2)
+  "Return true if n1 and n2 are connected and nil otherwise. connection represent
+the find operation on the Quick Union algorithm"
+  `(= (find-root ,network ,n1) (find-root ,network ,n2)))
+
+;; Link two nodes together
+(defun union_ (network n1 n2)
+  "Connect to sub-tree together. union represent the union operation on the Quick Union algorithm"
+  (let ((new-network (copy-seq network)))
+    (setf (elt new-network (find-root new-network n1))
+          (find-root new-network n2))
+    new-network))
+
+;; A consed version of union_
+(defmacro nunion_ (network n1 n2)
+  `(setf ,network (union_ ,network ,n1 ,n2)))
+