题解 | 数列求和
规律数列求和
http://www.nowcoder.com/practice/e05d1c142b3d4898be7183289a00ce5f
#include using namespace std;
int main() {
long long sum = 0;
long long a = 9;
long long b = 0;
for(int i = 1; i <= 10; i++)
{
sum = sum + a;
a = a*10;
b = b + sum;
}
cout << b << endl;
// write your code here......
return 0;
}
