看代码之前可以先看一下这篇文章以便更容易理解：https://blog.csdn.net/weixin_42881588/article/details/107085047
# 二叉树的实现 # 二叉树结点类 class TreeNode: def __init__(self, data=None, left=None, right=None): self.elem = data self.l_child = left self.r_child = right # 二叉树类 class Tree: # 创建空树 def __init__(self): self.root = TreeNode() self.incomplete = [] # 判空 def is_empty(self): return self.root.elem is None # 添加结点 def add(self, data): # 为新数据创建结点 tmp = TreeNode(data) # 若为空树：直接到对根结点赋值新结点 # 若为非空树：添加新节点到子树不完整的结点(incomplete) if self.is_empty(): self.root = tmp self.incomplete.append(self.root) else: first_incomplete = self.incomplete[0] if first_incomplete.l_child is None: # 左子节点为空：添加到左子节点处 first_incomplete.l_child = tmp self.incomplete.append(first_incomplete.l_child) else: # 右子节点为空：添加到右子节点处 first_incomplete.r_child = tmp self.incomplete.append(first_incomplete.r_child) self.incomplete.pop(0) # 先序遍历二叉树并显示 def front_show(self, tree): if tree is None: # 遍历到最后一层结点 return print(tree.elem) self.front_show(tree.l_child) self.front_show(tree.r_child) # 中序遍历二叉树并显示 def middle_show(self, tree): if tree is None: # 空树 return self.middle_show(tree.l_child) print(tree.elem) self.middle_show(tree.r_child) # 后序遍历二叉树并显示 def post_show(self, tree): if tree is None: # 空树 return self.post_show(tree.l_child) self.post_show(tree.r_child) print(tree.elem) # 广度优先遍历并显示 def level_show(self): if self.root is None: # 空树 return nodes = [] current = self.root nodes.append(current) while nodes: current = nodes.pop(0) print(current.elem) if current.l_child is not None: nodes.append(current.l_child) if current.r_child is not None: nodes.append(current.r_child) if __name__ == "__main__": # 产生10个数据放入二叉树中 values = range(10) my_tree = Tree() for value in values: my_tree.add(value) # 遍历二叉树 print(my_tree.root) print("前序遍历") my_tree.front_show(my_tree.root) print("中序遍历") my_tree.middle_show(my_tree.root) print("后序遍历") my_tree.post_show(my_tree.root) print("广度优先遍历") my_tree.level_show()