Data commit

Task/AVL-tree/Yabasic/avl-tree.basic

@@ -0,0 +1,147 @@
+// AVL-Tree C code, https://www.programiz.com/dsa/avl-tree
+// Ported to Yabasic by Galileo 2022/07
+
+KEY = 1 : LRIGHT = 2 : LLEFT = 3 : HEIGHT = 4
+
+root = 0 : ramas = 5 : indice = 0
+
+dim arbol(ramas, 4)
+
+
+sub rotateRight(y)
+    local x, T2
+
+    x = arbol(y, LLEFT)
+    T2 = arbol(x, LRIGHT)
+    arbol(x, LRIGHT) = y
+    arbol(y, LLEFT) = T2
+    arbol(y, HEIGHT) = max(height(arbol(y, LLEFT)), height(arbol(y, LRIGHT))) + 1
+    arbol(x, HEIGHT) = max(height(arbol(x, LLEFT)), height(arbol(x, LRIGHT))) + 1
+    return x
+end sub
+
+
+sub rotateLeft(x)
+    local y, T2
+
+    y = arbol(x, LRIGHT)
+    T2 = arbol(y, LLEFT)
+    arbol(y, LLEFT) = x
+    arbol(x, LRIGHT) = T2
+    arbol(x, HEIGHT) = max(height(arbol(x, LLEFT)), height(arbol(x, LRIGHT))) + 1
+    arbol(y, HEIGHT) = max(height(arbol(y, LLEFT)), height(arbol(y, LRIGHT))) + 1
+    return y
+end sub
+
+
+sub Balance(current)
+    return height(arbol(current, LLEFT)) - height(arbol(current, LRIGHT))
+end sub
+
+
+sub height(current)
+    return arbol(current, HEIGHT)
+end sub
+
+
+sub insert(current, key)
+    local balance
+
+    if current = 0 indice = indice + 1 : if indice > ramas then ramas = ramas + 5 : redim arbol(ramas, 4) endif : arbol(indice, KEY) = key : arbol(indice, HEIGHT) = 1 : return indice
+    if key < arbol(current, KEY) then
+        arbol(current, LLEFT) = insert(arbol(current, LLEFT), key)
+    elsif key > arbol(current, KEY) then
+        arbol(current, LRIGHT) = insert(arbol(current, LRIGHT), key)
+    else
+        return current
+    endif
+
+    arbol(current, HEIGHT) = max(height(arbol(current, LLEFT)), height(arbol(current, LRIGHT))) + 1
+    balance = Balance(current)
+    if balance > 1 and key < arbol(arbol(current, LLEFT), KEY) return rotateRight(current)
+    if balance < -1 and key > arbol(arbol(current, LRIGHT), KEY) return rotateLeft(current)
+    if balance > 1 and key > arbol(arbol(current, LLEFT), KEY) then
+        arbol(current, LLEFT) = rotateLeft(arbol(current, LLEFT))
+        return rotateRight(current)
+    endif
+    if balance < -1 and key < arbol(arbol(current, LRIGHT), KEY) then
+        arbol(current, LRIGHT) = rotateRight(arbol(current, LRIGHT))
+        return rotateLeft(current)
+    endif
+    return current
+end sub
+
+
+sub minValueNode(current)
+  while arbol(current, LLEFT)
+    current = arbol(current, LLEFT)
+  wend
+
+  return current
+end sub
+
+// Delete a nodes
+sub deleteNode(root, key)
+    local temp, balance
+  // Find the node and delete it
+  if root = 0 return root
+
+  if key < arbol(root, KEY) then
+    arbol(root, LLEFT) = deleteNode(arbol(root, LLEFT), key)
+  elsif key > arbol(root, KEY) then
+    arbol(root, LRIGHT) = deleteNode(arbol(root, LRIGHT), key)
+  else
+    if arbol(root, LLEFT) = 0 or arbol(root, LRIGHT) = 0 then
+      temp = max(arbol(root, LLEFT), arbol(root, LRIGHT))
+
+      if temp = 0 then
+        temp = root
+        root = 0
+      else
+        root = temp
+      endif
+    else
+      temp = minValueNode(arbol(root, LRIGHT))
+      arbol(root, KEY) = arbol(temp, KEY)
+      arbol(root, LRIGHT) = deleteNode(arbol(root, LRIGHT), arbol(temp, KEY))
+    endif
+  endif
+
+  if root = 0 return root
+
+  // Update the balance factor of each node and
+  // balance the tree
+  arbol(root, HEIGHT) = 1 + max(height(arbol(root, LLEFT)), height(arbol(root, LRIGHT)))
+
+  balance = Balance(root)
+  if balance > 1 and Balance(arbol(root, LLEFT)) >= 0 return rightRotate(root)
+  if balance > 1 and Balance(arbol(root, LLEFT)) < 0 arbol(root, LLEFT) = leftRotate(arbol(root, LLEFT)) : return rightRotate(root)
+  if balance < -1 and Balance(arbol(root, LRIGHT)) <= 0 return leftRotate(root)
+  if balance < -1 and Balance(arbol(root, LRIGHT)) > 0 arbol(root, LRIGHT) = rightRotate(arbol(root, LRIGHT)) : return leftRotate(root)
+
+  return root
+end sub
+
+sub preOrder(temp)
+    if temp then
+        print arbol(temp, KEY), " ", arbol(temp, HEIGHT), " ", Balance(temp)
+        preOrder(arbol(temp, LLEFT))
+        preOrder(arbol(temp, LRIGHT))
+    endif
+end sub
+
+
+  root = insert(root, 2)
+  root = insert(root, 1)
+  root = insert(root, 7)
+  root = insert(root, 4)
+  root = insert(root, 5)
+  root = insert(root, 3)
+  root = insert(root, 8)
+
+  preOrder(root)
+
+  root = deleteNode(root, 3)
+
+  print "\nAfter deletion: "
+  preOrder(root)