题解 | #数列求和#

public class Main {
    public static void main(String[] args) {

        //write your code here........

        long sum = 0;
        String init = "";

        while(!init.equals("9999999999")) {
            init += "9";
            sum += Long.parseLong(init);

//            System.out.print(init + " ");
        }

        System.out.print(sum);
    }
}