[Leetcode]#125 Valid Palindrome

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

For example,
“A man, a plan, a canal: Panama” is a palindrome.
“race a car” is not a palindrome.

Note:
Have you consider that the string might be empty? This is a good question to ask during an interview.

For the purpose of this problem, we define empty string as valid palindrome.

//#125 Valid Palindrome
//24ms 6.04%
#include <iostream>
#include <string>
using namespace std;

class Solution
{
public:
    bool isPalindrome(string s) 
    {
        bool valid(true);
        string::iterator it = s.begin();
        string::reverse_iterator r_it = s.rbegin();
        while(it != s.end() && r_it != s.rend())
        {
            while((*it < 48) || (*it < 65 && *it > 57) || *it > 122 || (*it < 97 && *it > 90))
            { 
                //cout << *it << endl;
                it++;
                if(it == s.end())
                {
                    break;
                }
            }
            while((*r_it < 48) || (*r_it < 65 && *r_it > 57)|| *r_it > 122 || (*r_it < 97 && *r_it > 90))
            { 
                //cout << *r_it << endl;
                r_it++;
                if(r_it == s.rend())
                {
                    break;
                }
            }

            if(it == s.end() && r_it == s.rend())
            {
                cout << "Reaching the ends\n";
                break;
            }           
            else if(*it == *r_it || *it == *r_it + 32 || *it == *r_it - 32)
            {
                //cout << "-OK-";
                it ++;
                r_it ++;
            }
            else
            {
                cout << "it " << *it << ", r_it "<< *r_it << endl;
                cout << "Different\n";
                valid = false;
                break;
            }
        }
        return valid;
    }
};