# coding = utf-8

 

 

class BinaryTree:

  def __init__(self, root_obj):

    self.key = root_obj

    self.left_child = None

    self.right_child = None

 

  def insert_left(self, new_node):

    node = BinaryTree(new_node)

    if self.left_child is None:

      self.left_child = node

    else:

      node.left_child = self.left_child

      self.left_child = node

 

  def insert_right(self, new_node):

    node = BinaryTree(new_node)

    if self.right_child is None:

      self.right_child = node

    else:

      node.right_child = self.right_child

      self.right_child = node

 

  def get_right_child(self):

    return self.right_child

 

  def get_left_child(self):

    return self.left_child

 

  def set_root_val(self, obj):

    self.key = obj

 

  def get_root_val(self):

    return self.key

 

 

root = BinaryTree('a')

print(root.get_root_val())

print(root.get_left_child())

root.insert_left('b')

print(root.get_left_child())

print(root.get_left_child().get_root_val())

root.insert_right('c')

print(root.get_right_child())

print(root.get_right_child().get_root_val())

root.get_right_child().set_root_val('hello')

print(root.get_right_child().get_root_val())
          

            
C:\Users\Sahara\.virtualenvs\test\Scripts\python.exe C:/Users/Sahara/PycharmProjects/test/python_search.py

a

None

<__main__.BinaryTree object at 0x00000000024139B0>

b

<__main__.BinaryTree object at 0x00000000024139E8>

c

hello

 

Process finished with exit code 0
          

            
 # -----------前序遍歷 ------------
  # 遞歸算法
  def pre_order_recursive(self, T):
    if T == None:
      return
    print(T.root, end=' ')
    self.pre_order_recursive(T.lchild)
    self.pre_order_recursive(T.rchild)

  # 非遞歸算法
  def pre_order_non_recursive(self, T):
    """借助棧實現前驅遍歷
    """
    if T == None:
      return
    stack = []
    while T or len(stack) > 0:
      if T:
        stack.append(T)
        print(T.root, end=' ')
        T = T.lchild
      else:
        T = stack[-1]
        stack.pop()
        T = T.rchild

          

            
# -----------中序遍歷 ------------
  # 遞歸算法
  def mid_order_recursive(self, T):
    if T == None:
      return
    self.mid_order_recursive(T.lchild)
    print(T.root, end=' ')
    self.mid_order_recursive(T.rchild)

  # 非遞歸算法
  def mid_order_non_recursive(self, T):
    """借助棧實現中序遍歷
    """
    if T == None:
      return
    stack = []
    while T or len(stack) > 0:
      if T:
        stack.append(T)
        T = T.lchild
      else:
        T = stack.pop()
        print(T.root, end=' ')
        T = T.rchild

          

            
# -----------后序遍歷 ------------
  # 遞歸算法
  def post_order_recursive(self, T):
    if T == None:
      return
    self.post_order_recursive(T.lchild)
    self.post_order_recursive(T.rchild)
    print(T.root, end=' ')

  # 非遞歸算法
  def post_order_non_recursive(self, T):
    """借助兩個棧實現后序遍歷
    """
    if T == None:
      return
    stack1 = []
    stack2 = []
    stack1.append(T)
    while stack1:
      node = stack1.pop()
      if node.lchild:
        stack1.append(node.lchild)
      if node.rchild:
        stack1.append(node.rchild)
      stack2.append(node)
    while stack2:
      print(stack2.pop().root, end=' ')
    return

          

            
# -----------層次遍歷 ------------
  def level_order(self, T):
    """借助隊列（其實還是一個棧）實現層次遍歷
    """
    if T == None:
      return
    stack = []
    stack.append(T)
    while stack:
      node = stack.pop(0) # 實現先進先出
      print(node.root, end=' ')
      if node.lchild:
        stack.append(node.lchild)
      if node.rchild:
        stack.append(node.rchild)
          

            
class NodeTree:
  def __init__(self, root=None, lchild=None, rchild=None):
    """創建二叉樹
    Argument:
      lchild: BinTree
        左子樹
      rchild: BinTree
        右子樹

    Return:
      Tree
    """
    self.root = root
    self.lchild = lchild
    self.rchild = rchild


class BinTree:

  # -----------前序遍歷 ------------
  # 遞歸算法
  def pre_order_recursive(self, T):
    if T == None:
      return
    print(T.root, end=' ')
    self.pre_order_recursive(T.lchild)
    self.pre_order_recursive(T.rchild)

  # 非遞歸算法
  def pre_order_non_recursive(self, T):
    """借助棧實現前驅遍歷
    """
    if T == None:
      return
    stack = []
    while T or len(stack) > 0:
      if T:
        stack.append(T)
        print(T.root, end=' ')
        T = T.lchild
      else:
        T = stack[-1]
        stack.pop()
        T = T.rchild

  # -----------中序遍歷 ------------
  # 遞歸算法
  def mid_order_recursive(self, T):
    if T == None:
      return
    self.mid_order_recursive(T.lchild)
    print(T.root, end=' ')
    self.mid_order_recursive(T.rchild)

  # 非遞歸算法
  def mid_order_non_recursive(self, T):
    """借助棧實現中序遍歷
    """
    if T == None:
      return
    stack = []
    while T or len(stack) > 0:
      if T:
        stack.append(T)
        T = T.lchild
      else:
        T = stack.pop()
        print(T.root, end=' ')
        T = T.rchild

  # -----------后序遍歷 ------------
  # 遞歸算法
  def post_order_recursive(self, T):
    if T == None:
      return
    self.post_order_recursive(T.lchild)
    self.post_order_recursive(T.rchild)
    print(T.root, end=' ')

  # 非遞歸算法
  def post_order_non_recursive(self, T):
    """借助兩個棧實現后序遍歷
    """
    if T == None:
      return
    stack1 = []
    stack2 = []
    stack1.append(T)
    while stack1:
      node = stack1.pop()
      if node.lchild:
        stack1.append(node.lchild)
      if node.rchild:
        stack1.append(node.rchild)
      stack2.append(node)
    while stack2:
      print(stack2.pop().root, end=' ')
    return

  # -----------層次遍歷 ------------
  def level_order(self, T):
    """借助隊列（其實還是一個棧）實現層次遍歷
    """
    if T == None:
      return
    stack = []
    stack.append(T)
    while stack:
      node = stack.pop(0) # 實現先進先出
      print(node.root, end=' ')
      if node.lchild:
        stack.append(node.lchild)
      if node.rchild:
        stack.append(node.rchild)

  # ----------- 前序遍歷序列、中序遍歷序列 ―> 重構二叉樹 ------------
  def tree_by_pre_mid(self, pre, mid):
    if len(pre) != len(mid) or len(pre) == 0 or len(mid) == 0:
      return
    T = NodeTree(pre[0])
    index = mid.index(pre[0])
    T.lchild = self.tree_by_pre_mid(pre[1:index + 1], mid[:index])
    T.rchild = self.tree_by_pre_mid(pre[index + 1:], mid[index + 1:])
    return T

  # ----------- 后序遍歷序列、中序遍歷序列 ―> 重構二叉樹 ------------
  def tree_by_post_mid(self, post, mid):
    if len(post) != len(mid) or len(post) == 0 or len(mid) == 0:
      return
    T = NodeTree(post[-1])
    index = mid.index(post[-1])
    T.lchild = self.tree_by_post_mid(post[:index], mid[:index])
    T.rchild = self.tree_by_post_mid(post[index:-1], mid[index + 1:])
    return T


if __name__ == '__main__':
  # ----------- 測試：前序、中序、后序、層次遍歷 -----------
  # 創建二叉樹
  nodeTree = NodeTree(1,
            lchild=NodeTree(2,
                    lchild=NodeTree(4,
                            rchild=NodeTree(7))),
            rchild=NodeTree(3,
                    lchild=NodeTree(5),
                    rchild=NodeTree(6)))
  T = BinTree()
  print('前序遍歷遞歸\t')
  T.pre_order_recursive(nodeTree) # 前序遍歷-遞歸
  print('\n')
  print('前序遍歷非遞歸\t')
  T.pre_order_non_recursive(nodeTree) # 前序遍歷-非遞歸
  print('\n')
  print('中序遍歷遞歸\t')
  T.mid_order_recursive(nodeTree) # 中序遍歷-遞歸
  print('\n')
  print('中序遍歷非遞歸\t')
  T.mid_order_non_recursive(nodeTree) # 中序遍歷-非遞歸
  print('\n')
  print('后序遍歷遞歸\t')
  T.post_order_recursive(nodeTree) # 后序遍歷-遞歸
  print('\n')
  print('后序遍歷非遞歸\t')
  T.post_order_non_recursive(nodeTree) # 后序遍歷-非遞歸
  print('\n')
  print('層次遍歷\t')
  T.level_order(nodeTree) # 層次遍歷
  print('\n')

  print('==========================================================================')

  # ----------- 測試：由遍歷序列構造二叉樹 -----------
  T = BinTree()
  pre = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I']
  mid = ['B', 'C', 'A', 'E', 'D', 'G', 'H', 'F', 'I']
  post = ['C', 'B', 'E', 'H', 'G', 'I', 'F', 'D', 'A']

  newT_pre_mid = T.tree_by_pre_mid(pre, mid) # 由前序序列、中序序列構造二叉樹
  T.post_order_recursive(newT_pre_mid) # 獲取后序序列
  print('\n')

  newT_post_mid = T.tree_by_post_mid(post, mid) # 由后序序列、中序序列構造二叉樹
  T.pre_order_recursive(newT_post_mid) # 獲取前序序列