125_valid_palindrome.java

class Solution {
    public boolean isPalindrome(String s) {
        String str = s.toLowerCase();
        int left = 0;
        int right = s.length() - 1;
        boolean ans = true;
        while (left < right) {
            if (Character.isLetterOrDigit(s.charAt(left)) == false) {
                left++;
                continue;
            }
            if (Character.isLetterOrDigit(s.charAt(right)) == false) {
                right--;
                continue;
            }
            if (str.charAt(left) != str.charAt(right)) {
                ans = false;
                break;
            } else {
                left++;
                right--;
            }
        }
        return ans;
    }
}

/**
 * This is my personal record of solving Leetcode Problems. 
 * If you have any questions, please discuss them in [Issues](https://github.com/mengxinayan/leetcode/issues).
 * Copyright (C) 2020-2022  mengxinayan
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */