leetcode Excel Sheet Column Number

原题链接：https://leetcode.com/problems/excel-sheet-column-number/

Description

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

class Solution {public:    int titleToNumber(string s) {        int ans = 0, k = 1;        size_t n = s.length();        reverse(s.begin(), s.end());        for (size_t i = 0; i < n; i++) {            int x = s[i] - 'A' + 1;            ans += (int)(x * pow(26, i));        }        return ans;    }};