leetcode Excel Sheet Column Number

题目连接

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

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