[Leetcode]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 

基本思路：把字母看成２６进制转换既可，等同于10,16进制转换

class Solution {public:    //A-Z:1-26, AA-AZ:27-52    int titleToNumber(string s) {        int sum = 0;        for(int i = 0;i < s.size();i++)            sum = sum*26 + s[i] - 'A' + 1;        return sum;    }};