125.验证回文串

LeetCode: https://leetcode.cn/problems/valid-palindrome/ (opens new window)

题目描述: 验证只考虑字母和数字字符的回文串

输入: "A man, a plan, a canal: Panama"
输出: true
解释："amanaplanacanalpanama" 是回文串

• 声明左右指针
• 将左右指针移动到有效的符号位置
• 开始比较

public boolean isPalindrome(String s) {
    char[] chars = s.toLowerCase().toCharArray();
    int left = 0;
    int right = chars.length - 1;
    while (left < right){
        while (left < right && !Character.isLetterOrDigit(chars[left])) {
            left++;
        }
        while (left < right  && !Character.isLetterOrDigit(chars[right])) {
            right--;
        }
        if (chars[left] == chars[right]){
            left++;
            right--;
        }else {
            return false;
        }
    }
    return true;
}