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 

class Solution {
public:
    int titleToNumber(string s) {
        int result = 0;
        //26进制转10进制，注意以'A'而不是0开头，因此要“+1”
        for(int i=0;i<s.length();++i)
        {
             result = result*26+(s[i]-'A'+1);
        }
        return result;
    }
};