[leetcode] 171. Excel Sheet Column Number 解题报告

题目链接：https://leetcode.com/problems/excel-sheet-column-number/

Related to question Excel Sheet Column Title

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 -> 28 

思路：很简单的一个26进制转换成10进制，有一个陷阱是没有说明大小写是等价的。

代码如下：

class Solution {public:    int titleToNumber(string s) {        int sum = 0;        for(int i = 0; i< s.size(); i++)            sum = sum*26 + toupper(s[i]) - 'A' + 1;        return sum;    }};

python

class Solution(object):    def titleToNumber(self, s):        """        :type s: str        :rtype: int        """        ans = 0        for index in range(len(s)):            ans = ans*26 + ord(s[index]) - ord('A') + 1        return ans;