✡ leetcode 171. Excel Sheet Column Number 字母转换为数字 --------- java

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 

很简单。

public class Solution {
    public int titleToNumber(String s) {
        int len = s.length();
        if (len == 0){
            return 0;
        }
        int num = 0;
        for (int i = 0; i < len; i++){
            num = num * 26 + s.charAt(i) - 'A' + 1;
        }
        return num;
    }
}