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https://github.com/TheAlgorithms/Python.git
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181 lines
4.8 KiB
Python
181 lines
4.8 KiB
Python
'''
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A AVL tree
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'''
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class Node:
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def __init__(self, label):
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self.label = label
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self._parent = None
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self._left = None
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self._right = None
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self.height = 0
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@property
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def right(self):
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return self._right
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@right.setter
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def right(self, node):
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if node is not None:
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node._parent = self
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self._right = node
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@property
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def left(self):
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return self._left
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@left.setter
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def left(self, node):
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if node is not None:
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node._parent = self
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self._left = node
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@property
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def parent(self):
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return self._parent
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@parent.setter
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def parent(self, node):
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if node is not None:
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self._parent = node
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self.height = self.parent.height + 1
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else:
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self.height = 0
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class AVL:
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def __init__(self):
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self.root = None
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self.size = 0
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def insert(self, value):
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node = Node(value)
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if self.root is None:
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self.root = node
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self.root.height = 0
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self.size = 1
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else:
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# Same as Binary Tree
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dad_node = None
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curr_node = self.root
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while True:
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if curr_node is not None:
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dad_node = curr_node
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if node.label < curr_node.label:
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curr_node = curr_node.left
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else:
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curr_node = curr_node.right
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else:
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node.height = dad_node.height
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dad_node.height += 1
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if node.label < dad_node.label:
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dad_node.left = node
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else:
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dad_node.right = node
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self.rebalance(node)
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self.size += 1
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break
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def rebalance(self, node):
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n = node
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while n is not None:
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height_right = n.height
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height_left = n.height
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if n.right is not None:
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height_right = n.right.height
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if n.left is not None:
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height_left = n.left.height
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if abs(height_left - height_right) > 1:
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if height_left > height_right:
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left_child = n.left
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if left_child is not None:
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h_right = (right_child.right.height
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if (right_child.right is not None) else 0)
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h_left = (right_child.left.height
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if (right_child.left is not None) else 0)
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if (h_left > h_right):
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self.rotate_left(n)
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break
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else:
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self.double_rotate_right(n)
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break
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else:
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right_child = n.right
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if right_child is not None:
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h_right = (right_child.right.height
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if (right_child.right is not None) else 0)
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h_left = (right_child.left.height
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if (right_child.left is not None) else 0)
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if (h_left > h_right):
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self.double_rotate_left(n)
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break
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else:
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self.rotate_right(n)
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break
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n = n.parent
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def rotate_left(self, node):
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aux = node.parent.label
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node.parent.label = node.label
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node.parent.right = Node(aux)
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node.parent.right.height = node.parent.height + 1
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node.parent.left = node.right
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def rotate_right(self, node):
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aux = node.parent.label
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node.parent.label = node.label
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node.parent.left = Node(aux)
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node.parent.left.height = node.parent.height + 1
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node.parent.right = node.right
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def double_rotate_left(self, node):
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self.rotate_right(node.getRight().getRight())
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self.rotate_left(node)
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def double_rotate_right(self, node):
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self.rotate_left(node.getLeft().getLeft())
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self.rotate_right(node)
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def empty(self):
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if self.root is None:
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return True
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return False
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def preShow(self, curr_node):
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if curr_node is not None:
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self.preShow(curr_node.left)
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print(curr_node.label, end=" ")
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self.preShow(curr_node.right)
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def preorder(self, curr_node):
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if curr_node is not None:
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self.preShow(curr_node.left)
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self.preShow(curr_node.right)
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print(curr_node.label, end=" ")
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def getRoot(self):
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return self.root
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t = AVL()
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t.insert(1)
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t.insert(2)
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t.insert(3)
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# t.preShow(t.root)
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# print("\n")
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# t.insert(4)
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# t.insert(5)
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# t.preShow(t.root)
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# t.preorden(t.root)
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