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本文实例讲述了Python数据结构之栈、队列及二叉树定义与用法。分享给大家供大家参考，具体如下：

目前只实现了三种，栈、队列和二叉树，哪天得空继续补吧~

1. 栈

#栈
class Stack:
  def __init__(self,size = 16):
    self.stack = []
    self.size = size
    self.top = -1
  def setSize(self, size):
    self.size = size
  def isEmpty(self):
    if self.top == -1:
      return True
    else:
      return False
  def isFull(self):
    if self.top +1 == self.size:
      return True
    else:
      return False
  def top(self):
    if self.isEmpty():
      raise Exception("StackIsEmpty")
    else:
      return self.stack[self.top]
  def push(self,obj):
    if self.isFull():
      raise Exception("StackOverFlow")
    else:
      self.stack.append(obj)
      self.top +=1
  def pop(self):
    if self.isEmpty():
      raise Exception("StackIsEmpty")
    else:
      self.top -= 1
      return self.stack.pop()
  def show(self):
    print(self.stack)
s = Stack(5)
s.push(1)
s.push(2)
s.push(3)
s.push(4)
s.push(5)
s.show()
s.pop()
s.show()
s.push(6)
s.show()

运行结果：

2. 队列

#队列
class Queue:
  def __init__(self,size = 16):
    self.queue = []
    self.size = size
    self.front = 0
    self.rear = 0
  def isEmpty(self):
    return self.rear == 0
  def isFull(self):
    if (self.front - self.rear +1) == self.size:
      return True
    else:
      return False
  def first(self):
    if self.isEmpty():
      raise Exception("QueueIsEmpty")
    else:
      return self.queue[self.front]
  def last(self):
    if self.isEmpty():
      raise Exception("QueueIsEmpty")
    else:
      return self.queue[self.rear]
  def add(self,obj):
    if self.isFull():
      raise Exception("QueueOverFlow")
    else:
      self.queue.append(obj)
      self.rear += 1
  def delete(self):
    if self.isEmpty():
      raise Exception("QueueIsEmpty")
    else:
      self.rear -=1
      return self.queue.pop(0)
  def show(self):
    print(self.queue)
q = Queue(3)
q.add(1)
q.add(2)
q.show()
q.delete()
q.show()

运行结果：

3. 二叉树

#队列
class Queue:
  def __init__(self,size = 16):
    self.queue = []
    self.size = size
    self.front = 0
    self.rear = 0
  def isEmpty(self):
    return self.rear == 0
  def isFull(self):
    if (self.front - self.rear +1) == self.size:
      return True
    else:
      return False
  def first(self):
    if self.isEmpty():
      raise Exception("QueueIsEmpty")
    else:
      return self.queue[self.front]
  def last(self):
    if self.isEmpty():
      raise Exception("QueueIsEmpty")
    else:
      return self.queue[self.rear]
  def add(self,obj):
    if self.isFull():
      raise Exception("QueueOverFlow")
    else:
      self.queue.append(obj)
      self.rear += 1
  def delete(self):
    if self.isEmpty():
      raise Exception("QueueIsEmpty")
    else:
      self.rear -=1
      return self.queue.pop(0)
  def show(self):
    print(self.queue)
#二叉树
class BinaryTreeNode:
  def __init__(self,data,left,right):
    self.left = left
    self.data = data
    self.right = right
class BinaryTree:
  def __init__(self):
    self.root = None
  def makeTree(self,data,left,right):
    self.root = BinaryTreeNode(data,left,right)
    #left.root = right.root = None
  def isEmpty(self):
    if self.root is None:
      return True
    else:
      return False
  def preOrder(self,r):
    if r.root is not None:
      print(r.root.data)
      if r.root.left is not None:
        self.preOrder(r.root.left)
      if r.root.right is not None:
        self.preOrder(r.root.right)
  def inOrder(self,r):
    if r.root is not None:
      if r.root.left is not None:
        self.inOrder(r.root.left)
      print(r.root.data)
      if r.root.right is not None:
        self.inOrder(r.root.right)
  def postOrder(self,r):
    if r.root is not None:
      if r.root.left is not None:
        self.preOrder(r.root.left)
      if r.root.right is not None:
        self.preOrder(r.root.right)
      print(r.root.data)
  def levelOrder(self,a):
    q = Queue()
    r = a
    while r is not None:
      print(r.root.data)
      if r.root.left is not None:
        q.add(r.root.left)
      if r.root.right is not None:
        q.add(r.root.right)
      if q.isEmpty():
        print("empty")
        r = None
      else:
        r = q.delete()
r = BinaryTree()
ra = BinaryTree()
ra.makeTree(2,None,None)
rb = BinaryTree()
rb.makeTree(3,None,None)
r.makeTree(1,ra,rb)
print("前序遍历")
r.preOrder(r)
print("中序遍历")
r.inOrder(r)
print("后序遍历")
r.postOrder(r)
print("层级遍历")
r.levelOrder(r)

运行结果: