為了練習尋找實習時會碰到的問題，我用別人推薦的 LeetCode online judge。
希望能直接寫程式，不用事先編譯就能直接AC。
這是下面是我寫的 Binary Tree Preorder Traversal 的解法。
To practice future interview question, I use LeetCode online judge.
I am trying to type code directly on website without compile in other tool.
The following program is my Binary Tree Preorder Traversal solution.
希望能直接寫程式，不用事先編譯就能直接AC。
這是下面是我寫的 Binary Tree Preorder Traversal 的解法。
To practice future interview question, I use LeetCode online judge.
I am trying to type code directly on website without compile in other tool.
The following program is my Binary Tree Preorder Traversal solution.
