[171]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

把问题当作26进制转10进制来做。

Code

Python

class Solution(object):
    def titleToNumber(self, s):
        """
        :type s: str
        :rtype: int
        """
        num = 0
        i = 0
        length = len(s)
        while i < length:
            num += 26**(len(s)-i-1)*(ord(s[i])-64)
            i += 1
        return num

Runtime: 36ms

Go

func titleToNumber(s string) int {
    result := 1
    length := len(s)
    result = result + int(s[0]-'A')
    for i := 1; i < length; i++ {
        result = result*26 + int(s[i]-'A') + 1
    }
    return int(result)
}