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。
下面是我寫的 Single Number 的解法。
這是改良後的版本，這邊是舊版本。
執行時間為 O(n), 並且沒用到額外記憶體!
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 Single Number solution.
It's a improved version. See the older version here.
Time complexity is O(n), ans I implement it without using extra memory.
希望能直接寫程式，不用事先編譯就能直接AC。
下面是我寫的 Single Number 的解法。
這是改良後的版本，這邊是舊版本。
執行時間為 O(n), 並且沒用到額外記憶體!
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 Single Number solution.
It's a improved version. See the older version here.
Time complexity is O(n), ans I implement it without using extra memory.
