题解 | #爬楼梯#

这道题。。。就考个大小越界，int不行、long也不行。。。我去

public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String i = sc.nextLine();
            long num = Long.parseLong(i);
            if(num==1) {
                System.out.println(1);
                continue;
            }
            BigDecimal pre = new BigDecimal(1);
            BigDecimal curr = new BigDecimal(2);
            for (int j = 0; j < num-2; j++) {
                BigDecimal tem = curr;
                curr = curr.add(pre);
                pre = tem;
            }
            System.out.println(curr.toString());
        }
    }