LeetCode125-验证回文串-双指针

原题链接

class Solution {
public:

    bool check(char c){
        if(c >= '0' && c <= '9' || c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z')
            return true;
        return false;
    }

    bool isPalindrome(string s) {
        int l = 0, r = s.size();

        while(l < r){
            while(l < r && !check(s[l]))   l ++;
            while(l < r && !check(s[r]))   r --;
            if(tolower(s[l]) != tolower(s[r]))    return false;
            l ++, r --;
        }
        
        return true;
    }
};