题解 | #数列求和#
数列求和
https://www.nowcoder.com/practice/6893484c04c24bfca1f606b1823a468d
public class Main { public static void main(String[] args) { //write your code here........ long n=10L; long sum=0L; while(n<=9999999999L+1){ sum += n-1; n *=10; } System.out.println(sum); } }