leetcode 日经贴，Cpp code -Excel Sheet Column Number

Excel Sheet Column Number

class Solution {public:    int titleToNumber(string s) {        int n = s.length();        int ret = 0, fact = 1;        for (int i = n - 1; i >= 0; --i) {            ret += (s[i] - 'A' + 1) * fact;            fact *= 26;        }        return ret;    }};