递归实现回文字符串的判断

import java.util.Scanner;

public class HuiWen {
    
    
   // private String txt;
    //回文字符串的判断 正读倒读都一样
    public static boolean HuiWen(String txt){
    
    
        //合法性判断
        if (txt==null||txt.length()==0){
    
    
            return false;
        }
          int i=0;
          int j=txt.length()-1;
          if (j>i){
    
    
              //满足递归终止条件给出的解决办法
              if (txt.charAt(i)!=txt.charAt(j)){
    
    
                  return false;
              }else {
    
    
                  //提取相同逻辑，缩小问题规模
                   HuiWen(txt.substring(i+1).substring(0,j-1));
              }

          }

                 return true;
    }


    public static void main(String[] args) {
    
    

        System.out.println(HuiWen("12321"));
        System.out.println(HuiWen("abccba"));
        System.out.println(HuiWen("12321wh"));

}


}