题解 | #规律数列求和#
规律数列求和
https://www.nowcoder.com/practice/e05d1c142b3d4898be7183289a00ce5f
#include <iostream>
#include<cmath>
using namespace std;
int main() {
// write your code here......
long long sum = 0;
long long arr = 0;
for(int i = 0;i<=9;i++)
{
//arr += (pow(10,i)*9);
arr = arr*10+9;
sum+=arr;
}
cout<<sum;
return 0;
}
