2496. Maximum Value of a String in an Array

The value of an alphanumeric string can be defined as:

• The numeric representation of the string in base 10, if it comprises of digits only.
• The length of the string, otherwise.

Given an array strs of alphanumeric strings, return the maximum value of any string in strs.

class Solution {
public:
    int maximumValue(vector<string>& strs) {
        long long res = 0;
        for(auto& s : strs) {
            bool fl = true;
            for(int i = 0; i < s.length(); i++) {
                if(isalpha(s[i])) fl = false;
            }
            if(!fl) res = max(res, (long long) s.length());
            else res = max(res, stoll(s));
        }
        return res;
    }
};