Valid Palindrome

基础

但是要掌握 int a = 'A'这种写法,以及

s.trim();
s = s.toUpperCase();

public class Solution {

    public boolean isPalindrome(String s) {

        if(s==null || s.length()<=1) return true;

        s.trim();

        s = s.toUpperCase();

        

        int low = 0, low1 = '0', low2 = 'A';

        int high = s.length()-1, high1 = '9', high2 = 'Z';

        while(low<high){

            if((s.charAt(low)<low1 || s.charAt(low)>high1) &&(s.charAt(low)<low2 || s.charAt(low)>high2)){

                low++;

                continue;

            }

            if((s.charAt(high)<low1 || s.charAt(high)>high1) &&(s.charAt(high)<low2 || s.charAt(high)>high2)){

                high--;

                continue;

            }

            if(s.charAt(low)==s.charAt(high)){

                high--;

                low++;

            }else

                return false;

        }

        return true;

    }

}