在Python中用栈实现深度优先树遍历

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

def dfs_tree_traversal(root):
    if root is None:
        return
    
    stack = [root]  # 使用栈来保存待访问的节点

    while stack:
        node = stack.pop()  # 弹出栈顶节点
        print(node.value)  # 访问节点的值

        # 先将右子节点入栈，再将左子节点入栈，保证左子节点先被访问
        if node.right:
            stack.append(node.right)
        if node.left:
            stack.append(node.left)

# 创建一个示例树
root = TreeNode(1)
root.left = TreeNode(2)
root.right = TreeNode(3)
root.left.left = TreeNode(4)
root.left.right = TreeNode(5)
root.right.left = TreeNode(6)
root.right.right = TreeNode(7)

# 执行深度优先树遍历
dfs_tree_traversal(root)