我這裡使用StringBuilder去reverse然後相加

程式碼如下：

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class c304 {
    /*  0.8s    15.1MB  */
    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            String n;
            while ((n = br.readLine()) != null)
                rev(n);
        } catch (Exception e) {
            System.out.println();
        }
    }

    static long rev(String n) {
        StringBuilder sb = new StringBuilder(n);
        String s = sb.reverse().toString();
        long res = Long.parseLong(s);
        res += Long.parseLong(n);
        System.out.println(res);
        return res;
    }
}