LeetCode 171. Excel Sheet Column Number

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题目

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

For example:

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8
A -> 1
B -> 2
C -> 3
...
Z -> 26
AA -> 27
AB -> 28 
...

Example 1:

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Input: "A"
Output: 1

Example 2:

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Input: "AB"
Output: 28

Example 3:

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Input: "ZY"
Output: 701

Constraints:

  • 1 <= s.length <= 7
  • s consists only of uppercase English letters.
  • s is between “A” and “FXSHRXW”.

思路

Easy.

代码

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