二叉树

#coding=utf-8


#构建二叉树（二叉树结点）
class Node(object):
    def __init__(self, data, left=None, right=None):
        self.data = data
        self.left = left
        self.right = right

tree = Node(1, Node(3, Node(7, Node(0)), Node(6)), Node(2, Node(5), Node(4)))


#层次遍历
def level_order(tree):
   if tree == None:
       return
   q = []
   q.append(tree)
   while q:
       current = q.pop(0)
       print(current.data)
       if current.left:
           q.append(current.left)
       if current.right:
           q.append(current.right)


#按层次打印
def level2_order(tree):
    if tree == None:
        return
    q = []
    q.append(tree)
    level = 0
    d = []
    result = {}
    next_level_num = 0
    current_level_num = 1
    while q:
        current = q.pop(0)
        current_level_num -= 1
        d.append(current.data)
        if current.left:
            q.append(current.left)
            next_level_num += 1
        if current.right:
            q.append(current.right)
            next_level_num += 1
        if current_level_num == 0:
            current_level_num = next_level_num
            next_level_num = 0
            result[level] = d
            level += 1
            d = []
    print(result)


#深度遍历
def deep(tree):
    if tree == None:
        return
    print(tree.data)
    deep(tree.left)
    deep(tree.right)


#前序遍历（根 左 右）
def pre_order(tree):
    if tree == None:
        return
    print(tree.data)
    if tree.left:
        pre_order(tree.left)
    if tree.right:
        pre_order(tree.right)


#中序遍历（左 根 右）
def mid_order(tree):
    if tree == None:
        return
    if tree.left:
        pre_order(tree.left)
    print(tree.data)
    if tree.right:
        pre_order(tree.right)


#后序遍历（ 左 右 根）
def post_order(tree):
    if tree == None:
        return
    if tree.left:
        pre_order(tree.left)
    if tree.right:
        pre_order(tree.right)
    print(tree.data)