class Solution {
public:
    bool isPalindrome(string s) {
        string s2;
        for(char x : s)
        {
            if(isalnum(x))
            {
                s2 += tolower(x);
            }
        }
        string s2_rev(s2.rbegin(),s2.rend());
        return s2 == s2_rev;
    }
};