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...... //+= 9*= (10*i) long long sum; for(int i = 0; i <= 10; i++) { sum += pow(10,i)-1; } cout<<sum<<endl; return 0; }
pow(10,i)-1 就是9,99,999...了