LeetCode 171. Excel Sheet Column Number

​​题目​​

class Solution {
public:
    int titleToNumber(string s) {
        
        int ans=0;
        for(int i=0;i<s.length();i++)
        {
            ans*=26;
            ans+=s[i]-'A'+1;

        }
        
        return ans;
        
    }
};