171. Excel Sheet Column Number

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

Excel Sheet Column Number - LeetCode

 

class Solution {
public:
    int titleToNumber(string s) {
        reverse(s.begin(), s.end());

        const int size = s.size();
        long long sol = s[0] - 'A'+ 1;
        for (int i = 1; i < size; i++) {
            char code = s[i] - 'A' + 1;
            long long cand = pow(26, i) * code;
            sol += cand;
        }
        return sol;
    }
};