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;
}
