Nowcoder 求数列的和

nowcoder-02f23a209c0c4d2484e29b560c174de1.cpp

// 精度取舍
#include<iostream>
#include<iomanip>
#include<cmath>

using namespace std;

inline double func(int a, int n) {
	return pow(a, pow(2, 1-n));
}

inline double calc(int n, int m) {
	double sum = 0.0;
	for (int i = 1; i <= m; ++i) {
		double delta = func(n, i);
		if (delta <= 0.001) return sum;
		sum += delta;
	}
    return sum;
}

int main() {
	cout << setiosflags(ios::fixed) << setprecision(2);
	int n, m; while (cin >> n >> m) {
		cout << calc(n, m) << endl;
	}
}