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  • 二叉搜索树的创建、遍历、插入、查找、删除

    import queue
    
    """
    二叉搜索树:
    特点:左子树的值小于根节点的值;右子树的值大于根节点的值
    1.创建
    2.插入节点
    3.广度优先遍历
    4.根据值查找节点
    5.删除节点
    """
    
    
    class TreeNode(object):
        """定义树的节点"""
    
        def __init__(self, val):
            self.value = val
            self.father = None
            self.left = None
            self.right = None
    
    
    class BinarySearchTree(object):
        def __init__(self, nodeList):
            """构建二叉搜索树"""
            self.root = None
            for node in nodeList:
                self.insert(node)
    
        def insert(self, node):
            """插入节点"""
            father = None
            cur = self.root
            # 找到要插入的位置
            while cur is not None:
                if cur.value == node.value:
                    return -1
                father = cur
                if node.value < cur.value:
                    cur = cur.left
                else:
                    cur = cur.right
            # 插入节点
            node.father = father
            if father is None:
                # print("插入根节点")
                self.root = node
            elif node.value < father.value:
                # print("插入左节点")
                father.left = node
            else:
                # print("插入右节点")
                father.right = node
    
        def breadthFirstSearch(self):
            """广度优先遍历"""
            if self.root is None:
                return None
            resultList = []
            q = queue.Queue()
            q.put(self.root)
            while not q.empty():
                node = q.get()
                # print(node.value)
                resultList.append(node.value)
                if node.left is not None:
                    q.put(node.left)
                if node.right is not None:
                    q.put(node.right)
            return resultList
    
        def search(self, value):
            """根据值查找节点"""
            cur = self.root
            while cur is not None:
                if cur.value == value:
                    return cur
                if value < cur.value:
                    cur = cur.left
                if value > cur.value:
                    cur = cur.right
            return None
    
        def deleteNode(self, node):
            """删除节点"""
            father = node.father
            # 删除的节点没有左子树,右子树代替删除的节点
            if node.left is None:
                # 删除的节点是根节点
                if father is None:
                    self.root = node.right
                    if node.right is not None:
                        node.right.father = None
                # 删除的节点不是根节点
                elif father.left == node:  # 删除的节点是左子节点
                    father.left = node.right
                    if node.right is not None:
                        node.right.father = father
                else:  # 删除的节点是右子节点
                    father.right = node.right
                    if node.right is not None:
                        node.right.father = father
                return 1
            # 删除的节点有左子树,右子树挂到左子树的最右节点
            tmpNode = node.left
            while tmpNode.right is not None:
                tmpNode = tmpNode.right
            tmpNode.right = node.right
            if node.right is not None:
                node.right.father = tmpNode
            # 删除的节点是根节点
            if father is None:
                self.root = node.left
                node.left.father = None
            # 删除的节点是左子节点
            elif father.left == node:
                father.left = node.left
                node.left.father = father
            # 删除的节点是右子节点
            else:
                father.right = node.left
                node.left.father = father
            # node=None
            return 2
    
    
    if __name__ == '__main__':
        data = [24, 34, 5, 4, 8, 23, 45, 35, 28, 6, 29]
        nodeList = [TreeNode(d) for d in data]
        # 构建二叉搜索树
        bst = BinarySearchTree(nodeList)
        # 广度优先遍历
        print(bst.breadthFirstSearch())
        # 根据值查找节点
        print(bst.search(23))
        node = bst.search(8)
        # 删除节点
        bst.deleteNode(node)
        print(bst.breadthFirstSearch())
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  • 原文地址:https://www.cnblogs.com/reyinever/p/11308033.html
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