二叉查找树.py

#!/usr/bin/python
# -*- coding: utf-8 -*-


class TreeNode:
    def __init__(self, key, val, left=None, right=None, parent=None) -> None:
        self.key = key
        self.payload = val
        self.leftChild = left
        self.rightChild = right
        self.parent = parent

    def hasLeftChild(self):
        return self.leftChild

    def hasRightChild(self):
        return self.rightChild

    def isLeftChild(self):
        return self.parent and self.parent.leftChild == self

    def isRightChild(self):
        return self.parent and self.parent.rightChild == self

    def isRoot(self):
        return not self.parent

    def isLeaf(self):
        return not (self.rightChild or self.leftChild)

    def hasAnyChildren(self):
        return self.rightChild or self.leftChild

    def hasBothChildren(self):
        return self.rightChild and self.leftChild

    def replaceNodeData(self, key, value, lc, rc):
        self.key = key
        self.payload = value
        self.leftChild = lc
        self.rightChild = rc

        if self.hasLeftChild():
            self.leftChild.parent = self
        if self.hasRightChild():
            self.rightChild.parent = self

    def __iter__(self):
        # 迭代器
        if self:
            if self.hasLeftChild():
                for elem in self.leftChild:
                    yield elem
            yield self.key
        if self.hasRightChild():
            for elem in self.rightChild:
                yield elem

    def findSuccessor(self):
        succ = None
        if self.hasRightChild():
            succ = self.rightChild.findMin()
        else:
            if self.parent:
                if self.isLeftChild():
                    succ = self.parent
                else:
                    self.parent.rightChild = None
                    succ = self.parent.findSuccessor()
                    self.parent.rightChild = self
        return succ

    def findMin(self):
        current = self
        while current.hasLeftChild():
            current = current.leftChild
        return current

    def spliceOut(self):
        if self.isLeaf():
            if self.isLeftChild():
                self.parent.leftChild = None
            else:
                self.parent.rightChild = None
        elif self.hasAnyChildren():
            if self.hasLeftChild():
                if self.isLeftChild():
                    self.parent.leftChind = self.leftChild
                else:
                    self.parent.rightChind = self.leftChild
                self.leftChild.parent = self.parent
            else:
                if self.isLeftChild():
                    self.parent.leftChind = self.rightChild
                else:
                    self.parent.rightChind = self.rightChild
                self.rightChild.parent = self.parent


class BinarySearchTree:
    # 构造b树
    def __init__(self) -> None:
        self.root = None
        self.size = 0

    def length(self):
        return self.size

    def __len__(self):
        return self.size

    def __iter__(self):
        return self.root.__iter__()

    def put(self, key, val):
        if self.root:
            self._put(key, val, self.root)
        else:
            self.root = TreeNode(key, val)
        self.size += 1

    def _put(self, key, val, currentNode):
        # 插入子树
        if key < currentNode.key:
            # 左子树
            if currentNode.hasLeftChild():
                self._put(key, val, currentNode.leftChild)
            else:
                currentNode.leftChild = TreeNode(key, val, parent=currentNode)
        else:
            if currentNode.hasRightChild():
                # 右子树
                self._put(key, val, currentNode.rightChild)
            else:
                currentNode.rightChild = TreeNode(key, val, parent=currentNode)

    def __setitem__(self, k, v):
        # 拦截字典传参数
        self.put(k, v)

    def get(self, key):
        if self.root:
            res = self._get(key, self.root)
            if res:
                return res.payload
            else:
                return None
        else:
            return None

    def _get(self, key, currentNode):
        if not currentNode:
            return None
        elif currentNode.key == key:
            return currentNode
        elif key < currentNode.key:
            return self._get(key, currentNode.leftChild)
        else:
            return self._get(key, currentNode.rightChild)

    def __getitem__(self, key):
        return self.get(key)

    def __contains__(self, key):
        if self._get(key, self.root):
            return True
        else:
            return False

    def remove(self, currentNode):
        if currentNode.isLeaf():
            # 没有子节点的方法，直接删除
            if currentNode == currentNode.parent.leftChild:
                currentNode.parent.leftChild = None
            else:
                currentNode.parent.rightChild = None
        elif currentNode.hasBothChildren():
            succ = currentNode.findSuccessor()
            succ.spliceOut()
            currentNode.key = succ.key
            currentNode.payload = succ.payload
        else:
            if currentNode.hasLeftChild():
                if currentNode.isLeftChild():
                    # 左子节点删除
                    currentNode.leftChild.parent = currentNode.parent
                    currentNode.parent.leftChild = currentNode.leftChild
                elif currentNode.isRightChild():
                    # 右子节点删除
                    currentNode.leftChild.parent = currentNode.parent
                    currentNode.parent.rightChild = currentNode.rightChild
                else:
                    # 根节点删除
                    currentNode.replaceNodeData(
                        currentNode.leftChild,
                        currentNode.leftChild.payload,
                        currentNode.leftChild.leftChild,
                        currentNode.leftChild.rightChild,
                    )
            else:
                if currentNode.isLeftChild():
                    # 左子节点删除
                    currentNode.rightChild.parent = currentNode.parent
                    currentNode.parent.leftChild = currentNode.leftChild
                elif currentNode.isRightChild():
                    # 右子节点
                    currentNode.rightChild.parent = currentNode.parent
                    currentNode.parent.rightChild = currentNode.rightChild
                else:
                    # 根节点删除
                    currentNode.replaceNodeData(
                        currentNode.rightChild,
                        currentNode.rightChild.payload,
                        currentNode.rightChild.leftChild,
                        currentNode.rightChild.rightChild,
                    )

    def delete(self, key):
        if self.size > 1:
            nodeToRemove = self._get(key, self.root)
            if nodeToRemove:
                self.remove(nodeToRemove)
                self.size -= 1
            else:
                raise KeyError("nof found key")

        elif self.size == 1 and self.root.key == key:
            self.root = None
            self.size -= 1
        else:
            raise KeyError("not found key")

    def __delitem__(self, key):
        self.delete(key)


if __name__ == "__main__":
    myTree = BinarySearchTree()
    # 字典传参数
    myTree[3] = "red"
    myTree[4] = "blue"
    myTree[6] = "yellow"
    myTree[2] = "at"

    # 归属判断
    print(3 in myTree)
    # 索引
    print(myTree[6])

    # 删除
    del myTree[3]

    # 循环
    for key in myTree:
        print(key, myTree[key])