125-Valid Palindrome.cpp

class Solution {
public:
    bool isPalindrome(string s)
    {
        for (int i=0,j=s.size()-1;i<j;i++,j--)
        {
            while(!isalnum(s[i])&&i<j)
                i++;
            while (!isalnum(s[j])&&i<j)
                j--;
            if(toupper(s[i])!=toupper(s[j]))
                return false;
        }  
        return true;
    }
};