题解 | #规律数列求和#

#include #include <math.h> using namespace std;

int main() {

// write your code here......
long long sum = 0;
//cin >> sum;
for(int i = 1; i <= 10; i++){
    sum += (pow(10 ,(long long)i) - 1);
}
cout << sum << endl;
return 0;

}