题解 | #规律数列求和#
规律数列求和
https://www.nowcoder.com/practice/e05d1c142b3d4898be7183289a00ce5f
#include <iostream> using namespace std; int main() { // write your code here...... cout<<9+99+999+9999+99999+999999+9999999+99999999+999999999+9999999999<<endl; return 0; }