Python 实现列表与二叉树相互转换并打印二叉树封装类-详细注释+完美对齐

# Python 实现列表与二叉树相互转换并打印二叉树封装类-详细注释+完美对齐
from binarytree import build
import random

# https://www.cnblogs.com/liw66/p/12133451.html

class MyBinaryTree:
    lst = []

    def __init__(self, lst=[]):
        MyBinaryTree.lst = lst

    class TreeNode:
        def __init__(self, val=0, left=None, right=None):
            self.val = val
            self.left = left
            self.right = right

    def getTreeFromList(self, _list=None):
        if _list is None: _list = MyBinaryTree.lst
        if _list is None: return []

        len_all = len(_list)  # 整个列表的长度
        lay = 0  # 层数
        loc = 0  # 结果列表位置
        lay_list = []  # 层列表
        node_list = []  # 节点列表
        while len_all > 0:
            len_lay = pow(2, lay)  # 层列表的长度，每层的长度为 2^lay，2^0、2^1、2^2、2^3、...
            lay_list.append(_list[loc:(loc + len_lay)])  # 从 _list 切片得到该层的元素列表，添加到 lay_list 中
            tail = len(lay_list) - 1  # lay_list 的尾节点索引
            # 对 lay_list 的尾节点（每个节点元素都为列表）进行循环遍历，用列表中的每个元素构建TreeNode添加到node_list中
            for j in range(len(lay_list[tail])):
                # 转换层列表为：[[5], [2, 9], [10, 1, 10, 5], [0, 9, 1]]
                node_list.append(MyBinaryTree.TreeNode(lay_list[tail][j]))  # 将列表索引 j 元素构建TreeNode添加到node_list中

                # 为上一层的父节点 TreeNode 元素添加 left、或right 值
                # if lay_list[tail][j] and lay > 0:  # 在 python 中0、空都为假，非零为真，所以这样将导致 lay_list[tail][j] 为 0 时没能填充
                if lay_list[tail][j] is not None and lay > 0:  # 必须改为这样，才能避免 lay_list[tail][j] 为 0 时没能填充
                    if j % 2 == 0:
                        node_list[pow(2, lay - 1) - 1 + j // 2].left = node_list[-1]
                    else:
                        node_list[pow(2, lay - 1) - 1 + j // 2].right = node_list[-1]

            loc += len_lay
            len_all -= len_lay
            lay += 1

        return node_list, lay_list

    def getListFromTree(self, root=None):
        node_list = []
        if root is None:
            node_list = self.getTreeFromList()[0]

        root = node_list[0]

        def treeRecursion(root, i, _list):
            if root is None:
                return

            len1 = len(_list)
            if len1 <= i:
                for j in range(i - len1 + 1):
                    _list.append(None)

            _list[i] = root.val
            treeRecursion(root.left, 2 * i, _list)
            treeRecursion(root.right, 2 * i + 1, _list)

        _list = []
        treeRecursion(root, 1, _list)
        while _list and _list[0] is None:
            del (_list[0])
        return _list

    def printTree(self, node_list=[]):
        if node_list is None:
            node_list, _ = self.getTreeFromList()

        def getNodeName(node, name="Node"):
            return "None" if node is None or node.val is None else name + "{:0>2d}".format(node.val)

        print("node:".ljust(7), "val".ljust(5), "left".ljust(7), "right")
        for node in range(len(node_list)):
            print(getNodeName(node_list[node]).ljust(6), end=": ")
            print((getNodeName(node_list[node], "") + ", ").ljust(6),
                  (getNodeName(node_list[node].left) + ", ").ljust(8),
                  getNodeName(node_list[node].right), sep='')

def test_binarytree(list1):
    mytree = MyBinaryTree(list1)

    list2 = mytree.getListFromTree()
    print("转换后列表为：{}".format(list2))
    print("原来的列表为：{}".format(list1))
    print("转换层列表为：{}".format(mytree.getTreeFromList()[1]))
    print("转换前后的的列表是否相等：{}".format(list1 == list2))

    print()
    print("原来的列表转换为二叉树：{}".format(build(list1)))
    print("转换的列表转换为二叉树：{}".format(build(list2)))

    print("二叉树节点列表为（完美对齐）：")
    mytree.printTree(mytree.getTreeFromList()[0])

list1 = [0, 1, 2, 3, 4, 5, 6, None, 7, None, 9, None, None, 10, ]
# list1 = [i for i in range(100)]
# list1 = [random.randint(0, 99) for i in range(20)]
test_binarytree(list1)

# S:\PythonProject\pyTest01\venv\Scripts\python.exe S:/PythonProject/pyTest01/main.py
# 转换后列表为：[0, 1, 2, 3, 4, 5, 6, None, 7, None, 9, None, None, 10]
# 原来的列表为：[0, 1, 2, 3, 4, 5, 6, None, 7, None, 9, None, None, 10]
# 转换层列表为：[[0], [1, 2], [3, 4, 5, 6], [None, 7, None, 9, None, None, 10]]
# 转换前后的的列表是否相等：True
#
# 原来的列表转换为二叉树：
#       ____0__
#      /       \
#   __1         2___
#  /   \       /    \
# 3     4     5     _6
#  \     \         /
#   7     9       10
#
# 转换的列表转换为二叉树：
#       ____0__
#      /       \
#   __1         2___
#  /   \       /    \
# 3     4     5     _6
#  \     \         /
#   7     9       10
#
# 二叉树节点列表为（完美对齐）：
# node:   val   left    right
# Node00: 00,   Node01, Node02
# Node01: 01,   Node03, Node04
# Node02: 02,   Node05, Node06
# Node03: 03,   None,   Node07
# Node04: 04,   None,   Node09
# Node05: 05,   None,   None
# Node06: 06,   Node10, None
# None  : None, None,   None
# Node07: 07,   None,   None
# None  : None, None,   None
# Node09: 09,   None,   None
# None  : None, None,   None
# None  : None, None,   None
# Node10: 10,   None,   None
#
# 进程已结束,退出代码0