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...... long long sum=0; for(long long j=10;j<=10000000000;j*=10){ sum+=(j-1); } cout<<sum; return 0; }