☆打卡算法☆LeetCode 125. 验证回文串 算法解析

示例 1：
输入: "A man, a plan, a canal: Panama"
输出: true
解释： "amanaplanacanalpanama" 是回文串

示例 2：
输入: "race a car"
输出: false
解释： "raceacar" 不是回文串

class Solution {
    public boolean isPalindrome(String s) {
        StringBuffer sgood = new StringBuffer();
        int length = s.length();
        for (int i = 0; i < length; i++) {
            char ch = s.charAt(i);
            if (Character.isLetterOrDigit(ch)) {
                sgood.append(Character.toLowerCase(ch));
            }
        }
        StringBuffer sgood_rev = new StringBuffer(sgood).reverse();
        return sgood.toString().equals(sgood_rev.toString());
    }
}