基于python的二叉搜索树

二叉搜索树即左孩子<=根节点，右孩子>=根节点

# -*- coding: utf-8 -*-
# @Time    : 2018/9/23 21:10
# @Author  : Lemon_shark
# @Email   : [email protected]

class TreeNode:
    def __init__(self,value):
        self.value=value
        self.left=None
        self.right=None

class bst_Method:
    def tree_Create(self,root,val):
        if root==None:
            root=TreeNode(val)
        elif valroot.value:
            root.right=self.tree_Create(root.right,val)
        return root

    def tree_Query(self,root,val):
        if root==None:
            return
        if root.value==val:
            return root.value
        elif root.value>val:
            return self.tree_Query(root.left,val)
        elif root.value>val:
            return self.tree_Query(root.right,val)

    def delNode(self, root, val):
        '''删除二叉搜索树中值为val的点'''
        if root == None:
            return
        if val < root.value:
            root.left = self.delNode(root.left, val)
        elif val > root.value:
            root.right = self.delNode(root.right, val)
        # 当val == root.val时，分为三种情况：只有左子树或者只有右子树、有左右子树、即无左子树又无右子树
        else:
            if root.left and root.right:
                # 既有左子树又有右子树，则需找到右子树中最小值节点
                temp = self.find_Min(root.right)
                root.value = temp.value
                # 再把右子树中最小值节点删除
                root.right = self.delNode(root.right, temp.value)
            elif root.right == None and root.left == None:
                # 左右子树都为空
                root = None
            elif root.right == None:
                # 只有左子树
                root = root.left
            elif root.left == None:
                # 只有右子树
                root = root.right
        return root

    def find_Min(self,root):
        if root.left:
            return self.find_Min(root.left)
        else:
            return root

    def find_Max(self,root):
        if root.right:
            return self.find_Max(root.right)
        else:
            return root

    def tree_Print(self,root):
        if root==None:
            return
        self.tree_Print(root.left)
        print(root.value,end=' ')
        self.tree_Print(root.right)


if __name__=='__main__':
    List = [17, 5, 35, 2, 11, 29, 38, 9, 16, 8]
    root=None
    op=bst_Method()
    for i in List:
        root=op.tree_Create(root,i)
    print('中序遍历，二叉搜索树的中序遍历是有序的')
    op.tree_Print(root)
    print('')
    print('根节点的值为：', root.value)
    print('树中最大值为:', op.find_Max(root).value)
    print('树中最小值为:', op.find_Min(root).value)
    print('查询树中值为5的节点:', op.tree_Query(root, 5))
    print('查询树中值为100的节点:', op.tree_Query(root, 100))
    print('删除树中值为16的节点:', end=' ')
    root = op.delNode(root, 16)
    op.tree_Print(root)
    print('')
    print('删除树中值为5的节点:', end=' ')
    root = op.delNode(root, 5)
    op.tree_Print(root)
    print('')

输出结果为：