LeetCode 171 [Excel Sheet Column

原题

Given a column title as appear in an Excel sheet, return its corresponding column number.

样例

    A -> 1
    B -> 2
    C -> 3
    ...
    Z -> 26
    AA -> 27
    AB -> 28 

解题思路

• 题目本质就是26进制转化为10进制

完整代码

class Solution(object):
    def titleToNumber(self, s):
        """
        :type s: str
        :rtype: int
        """
        res = 0
        for letter in s:
            res = res * 26 + (ord(letter) - ord('A') + 1)
        return res