Python实现二叉树

使用python实现的一个二叉树的实现方式(更新中)

对应letcode--538. Convert BST to Greater Tree

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

class Solution(object):
    def convertBST(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """

        def visit1(root):
            if root:
                visit1(root.left)
                vals.append(root.val)
                visit1(root.right)

        vals = []
        visit1(root)
        self.s = 0

        def visit2(root):
            if root:
                visit2(root.right)
                self.s += vals.pop()
                root.val = self.s
                visit2(root.left)
        visit2(root)
        return root

input_5=TreeNode(5)
input_18=TreeNode(18)
input_all=TreeNode(2)
input_all.left=input_5
input_all.right=input_18
slu_=Solution()
print input_all
t=slu_.convertBST(input_all)
print t

关于二叉树的相关的操作如下

class TreeNode(object):
    def __init__(self,data=0,left=0,right=0):
        self.data = data
        self.left = left
        self.right = right


class BTree(object):
    def __init__(self,root=0):
        self.root = root

    def is_empty(self):
        if self.root is 0:
            return True
        else:
            return False

    def preOrder(self,treenode):
        if treenode is 0:
            return
        print treenode.data
        self.preOrder(treenode.left)
        self.preOrder(treenode.right)

    def inOrder(self,treenode):
        if treenode is 0:
            return
        self.inOrder(treenode.left)
        print treenode.data
        self.inOrder(treenode.right)

    def postOrder(self,treenode):
        if treenode is 0:
            return
        self.postOrder(treenode.left)
        self.postOrder(treenode.right)
        print treenode.data
n1 = TreeNode(data=1)
n2 = TreeNode(2,n1,0)
n3 = TreeNode(3)
n4 = TreeNode(4)
n5 = TreeNode(5,n3,n4)
n6 = TreeNode(6,n2,n5)
n7 = TreeNode(7,n6,0)
n8 = TreeNode(8)
root = TreeNode('root',n7,n8)

bt = BTree()
print 'preOrder......'
print bt.preOrder(root)
print 'inOrder......'
print bt.inOrder(bt.root)
print 'postOrder.....'
print bt.postOrder(bt.root)