二叉树的功能实现

Posted 2021-02-18 hude

 

# 树的单个结点
class Node:
    def __init__(self,elem):
        # 结点数据
        self.elem = elem
        # 左子树和右子树
        self.lchild = None
        self.rchild = None

# 二叉树的实现
class my_tree:
    # 初始化空树
    def __init__(self):
        self.root = None
    # 树添加元素，广度遍历 + 队列
    def add(self,item):
        # 创建新结点
        node = Node(item)
        # 特殊情况
        if self.root is None:
            self.root = node
            return
        else:
            # 队列的方式实现，队列最开始存根
            queue = [self.root]
            # 循环处理队列，直到将新结点添加进树为止
            while queue:
                # 取出第一个未处理的结点
                cur_node = queue.pop(0)
                # 判断取出的结点有没有左或右
                # 左结点是空，则添加新结点
                if cur_node.lchild is None:
                    cur_node.lchild = node
                    return
                else:
                    # 左结点不是空，则将左结点添加进队列
                    queue.append(cur_node.lchild)
                if cur_node.rchild is None:
                    cur_node.rchild = node
                    return
                else:
                    queue.append((cur_node.rchild))
# 广度遍历
# 广度遍历
def tree_travle(self):
    if self.root is None:
        return
    else:
        # 队列先存根结点
        queue = [self.root]
        while queue:
            # 取第一个未处理的结点
            cur_node = queue.pop(0)
            print(cur_node.elem, end=‘ ‘)
            if cur_node.lchild is not None:
                queue.append(cur_node.lchild)
            if cur_node.rchild is not None:
                queue.append(cur_node.rchild)
# 深度遍历
    # 深度遍历
    # 先序 根左右
    def xian(self, root):
        if root == None:
            return
        else:
            print(root.elem, end=‘ ‘)
            # 递归
            self.xian(root.lchild)
            self.xian(root.rchild)
    # 中序 左根右
    def zhong(self,root):
        if root == None:
            return
        else:
            self.zhong(root.lchild)
            print(root.elem,end=‘ ‘)
            self.zhong(root.rchild)
    # 后序 左右根
    def hou(self,root):
        if root == None:
            return
        else:
            self.hou(root.lchild)
            self.hou(root.rchild)
            print(root.elem,end=‘ ‘)

if __name__ == ‘__main__‘:
    tree = my_tree()
    tree.add(0)
    tree.add(1)
    tree.add(2)
    tree.add(3)
    tree.add(4)
    tree.add(5)
    tree.add(6)
    tree.add(7)
    tree.add(8)
    tree.add(9)
    # 广度
    tree.tree_travle()
    print(‘‘)
    # 先序
    tree.xian(tree.root)
    print(‘‘)
    # 中序
    tree.zhong(tree.root)
    print(‘‘)
    # 后序
    tree.hou(tree.root)