摘要：
In a given grid, each cell can have one of three values: the value 0 representing an empty cell; the value 1 representing a fresh orange; the value 2 阅读全文
摘要：
Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example: 1 -> A 2 -> B 3 -> C ... 26 -> Z 27 -> AA 28 阅读全文
摘要：
Given a column title as appear in an Excel sheet, return its corresponding column number. For example: A -> 1 B -> 2 C -> 3 ... Z -> 26 AA -> 27 AB -> 阅读全文