力扣刷题125. 验证回文串

125. 验证回文串 - 力扣（LeetCode）

直接遍历字符串即可，用stringbuilder 中的service反转字符串，然后再用equalsIgnoreCase进行判断

class Solution {public boolean isPalindrome(String s) {StringBuilder sb = new StringBuilder();for (int i = 0; i < s.length(); i++) {char c = s.charAt(i);int num =  c;//System.out.println(num);if ((num >= 65 && num <= 90) || (num >= 97 && num <= 122)|| (num >= 48 && num <= 57)){//System.out.println(c);sb.append(c);}}String s1 = sb.toString();String s2 = sb.reverse().toString();
//        System.out.println(s1);
//       System.out.println(s2);if(s1.equalsIgnoreCase(s2))return true;else return false;}
}