AVL树添加及自旋python实现

from collections import deque
from dataStructures.tree.biTree.bst import BiTreeNode, BST

class AVLNode(BiTreeNode):
    def __init__(self, data):
        BiTreeNode.__init__(self, data)
        self.bf = 0 #存平衡因子

class AVLTree(BST):
    def __init__(self, li=None):
        BST.__init__(self, li)

    def rotate_left(self, p, c):
        #c是当前node，p是node.parent
        s2 = c.lchild
        p.rchild = s2
        if s2:
            s2.parent = p

        c.lchild = p
        p.parent = c

        p.bf = 0
        c.bf = 0
        return c

    def rotate_right(self, p, c):
        s2 = c.rchild
        p.lchild = s2
        if s2:
            s2.parent = p

        c.rchild = p
        p.parent = c

        p.bf = 0
        c.bf = 0
        return c

    def rotate_right_left(self, p, c):
        g = c.lchild
        # 先右旋，变成右右结构
        s3 = g.rchild
        c.lchild = s3
        if s3:
            s3.parent = c
        g.rchild = c
        c.parent = g

        s2 = g.lchild
        p.rchild = s2
        if s2:
            s2.parent = p
        g.lchild = p
        p.parent = g

        # 更新bf（右边-左边）
        # （1）插入s3
        if g.bf > 0:
            p.bf = -1
            c.bf = 0
        # （2）插入s2

        elif g.bf < 0:
            p.bf = 0
            c.bf = 1
        else: # 插入的是g
            p.bf = 0
            c.bf = 0
            # 插入的是g（意味着s1、s2、s3、s4为空）
        return g

    def rotate_left_right(self, p, c):
        g = c.rchild

        s2 = g.lchild
        c.rchild = s2
        if s2:
            s2.parent = c
        g.lchild = c
        c.parent = g

        s3 = g.rchild
        p.lchild = s3
        if s3:
            s3.parent = p
        g.rchild = p
        p.parent = g

        # 更新bf
        if g.bf < 0:    # 插入s2
            p.bf = 1
            c.bf = 0
        elif g.bf > 0:  # 插入s3
            p.bf = 0
            c.bf = -1
        else:
            p.bf = 0
            c.bf = 0
        return g



    def insert_no_rec(self, val):
        # 1. 和BST一样，插入
        p = self.root
        if not p:  # 空树
            self.root = AVLNode(val)
            return
        while True:
            if val < p.data:
                if p.lchild:
                    p = p.lchild    # node存储就是插入的结点
                else:  # 左孩子不存在
                    p.lchild = AVLNode(val)
                    p.lchild.parent = p
                    node = p.lchild # node 存储的就是插入的节点
                    break
            elif val > p.data:
                if p.rchild:
                    p = p.rchild
                else:
                    p.rchild = AVLNode(val)
                    p.rchild.parent = p
                    node = p.rchild
                    break
            else:   # val == p.data
                return

        # 2. 更新balance factor
        while node.parent:  # node.parent不空
            if node.parent.lchild == node: # 传递是从左子树来的，左子树更沉了
                #更新node.parent的bf -= 1
                if node.parent.bf < 0: # 原来node.parent.bf == -1, 更新后变成-2
                    # 做旋转
                    # 看node哪边沉
                    g = node.parent.parent # 为了连接旋转之后的子树
                    x = node.parent  # 旋转前的子树的根
                    #从当前node.bf判断是左边插入还是右边
                    if node.bf > 0:
                        n = self.rotate_left_right(node.parent, node)   # n为旋转之后子树的头节点
                    else:
                        n = self.rotate_right(node.parent, node)
                    # 记得：把n和g连起来
                elif node.parent.bf > 0: # 原来node.parent.bf = 1，更新之后变成0
                    node.parent.bf = 0
                    break
                else: # 原来node.parent.bf = 0，更新之后变成-1
                    node.parent.bf = -1
                    node = node.parent
                    continue
            else: # 传递是从右子树来的，右子树更沉了
                #更新node.parent.bf += 1
                if node.parent.bf > 0:  # 原来node.parent.bf == 1, 更新后变成2
                    # 做旋转
                    # 看node哪边沉
                    g = node.parent.parent # 为了连接旋转之后的子树
                    x = node.parent  # 旋转前的子树的根
                    #➡由此判断是父节点的左子树还是右子树
                    if node.bf < 0: # node.bf = -1
                        #右左结构
                        n = self.rotate_right_left(node.parent, node)
                    else:   # node.bf = 1
                        #右右结构
                        n = self.rotate_left(node.parent, node)
                    # 记得连起来
                elif node.parent.bf < 0: # 原来node.parent.bf = -1，更新之后变成0
                    node.parent.bf = 0
                    break
                else: # 原来node.parent.bf = 0，更新之后变成1
                    node.parent.bf = 1
                    node = node.parent
                    continue

            # 链接旋转后的子树
            n.parent = g
            if g: # g不是空
                #判断原来是在左孩子还是右孩子
                if x == g.lchild:
                    g.lchild = n
                else:
                    g.rchild = n
                break
            else:
                self.root = n
                break

    def level_order(self, root):
        queue = deque()
        queue.append(root)
        while len(queue) > 0:
            node = queue.popleft()
            print(node.data, end=',')
            if node.lchild:
                queue.append(node.lchild)
            if node.rchild:
                queue.append(node.rchild)


tree = AVLTree([10,5,0])