图解精选 TOP 面试题 006 | 进制转换

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

输入: "A"
输出: 1

输入: "AB"
输出: 28

输入: "ZY"
输出: 701

class Solution:
    def titleToNumber(self, s: str) -> int:
        res = 0

        ans = 1

        for word in s[::-1]:
            res += ans * (ord(word) - ord('A') + 1)
            ans *= 26

        return res

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