Pre-order traversal of the following binary tree:对以下二叉树进行先序遍历:Lco答案窝(daanwo.com)-大学生作业答案及考资分享平台

When you have just finished accessing node d (Implementation 2), the elements in the stack from the top of the stack to the bottom of the stack are:刚访问完节点d时（迭代实现2）栈中的元素从栈顶到栈底依次为:Lco答案窝(daanwo.com)-大学生作业答案及考资分享平台

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