檢查 $n$ 是否為 3 的次方。Check $n$ whether it is a power of three or not.

檢查兩個 array 中相同的元素。Return elements must appear as many times as it shows in both arrays

回傳所有可行的座標中，距離最短的點。Return the index of the valid point with the smallest Manhattan distance from your current location.

將兩個已經排序過的 array 合併。Merge nums1 and nums2 into a single array sorted in non-decreasing order.

兩個字串進行二進位數值加法，並回傳字串。Given two binary strings a and b, return their sum as a binary string.

尋求低買高賣的最大獲利。Return the maximum of the profits.