public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scanner = new Scanner(System.in);
System.out.println(cal(scanner.nextInt()));
}
static String cal(int n)
{
if(n==1)
{
return "A";
}
else {
return cal(n-1)+(char)(‘A‘+n-1)+cal(n-1);
}
}蓝桥杯——基础练习之FJ的字符串,布布扣,bubuko.com
原文：http://blog.csdn.net/hymanxq/article/details/25836453