python 實現二叉樹相關演算法

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一、構建與遍曆二叉樹

 

class Node(object):    def __init__(self,item):        self.key=item        self.left=None        self.right=None

 

class BinaryTree(object):    def __init__(self):        self.root=None    def addNode(self,item):        new_node = Node(item)        if self.root is None:           self.root=new_node        else:            stack=[]            stack.append(self.root)            while True:                node=stack.pop(0)                if node.left is None:                    node.left=new_node                    return                elif node.right is None:                    node.right=new_node                    return                else:                    stack.append(node.left)                    stack.append(node.right)    def traverse(self):  #層次遍曆        if self.root is None:            return None        else:            s=[]            s.append(self.root)            while len(s) > 0:                node = s.pop(0)                print(node.key)                if node.left is not None:                    s.append(node.left)                if node.right is not None:                    s.append(node.right)    def preOrder(self,root):        if root is None:            return None        print(root.key)        self.preOrder(root.left)        self.preOrder(root.right)    def inOrder(self,root):        if root is None:            return None        self.inOrder(root.left)        print(root.key)        self.inOrder(root.right)    def postOrder(self,root):        if root is None:            return None        self.postOrder(root.left)        self.postOrder(root.right)        print(root.key)

 

python 實現二叉樹相關演算法