[LeetCode 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

solution:

26 进制，逐位＊26相加

public int titleToNumber(String s) {
        if(s == null ||s.isEmpty()) return 0;
        if(s.length()==1) return s.charAt(0)-'A'+1;
        int result = s.charAt(0)-'A'+1;
        for(int i=1;i<s.length();i++){
            int cur = s.charAt(i)-'A'+1;
            result = result*26 + cur;
        }
        return result;
    }