30.leetcode171_excel_sheet_column_number

Posted 2020-10-24 vlice

1.题目描述

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 

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

26进制转10进制

2.题目分析

从字符串末尾开始遍历，依次加数

3.解题思路

 1 class Solution(object):
 2     def titleToNumber(self, s):
 3         """
 4         :type s: str
 5         :rtype: int
 6         """
 7         l=len(s)
 8         i=l-1
 9         temp=ord(‘A‘)-1
10         n=0
11         while i>=0:
12             n+=26**(l-i-1)*(ord(s[i])-temp)
13             i-=1
14         return n
15