题解 | #数列的和#

import java.util.Scanner;

public class Main {

    /**
     * 数列 n .. 的前 m 项和
     * 输入：81 4     2 2
     * 输出: 94.73    3.41
     */
    public static void main(String[] args) {
        run();
    }

    private static void nSum(int n, int m) {
        double res = n;
        double sum = 0;
        for (int i = 0; i < m; i++) {
            sum += res;
            res = Math.sqrt(res);
        }
        System.out.println(String.format("%.2f", sum));
    }

    private static void run() {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String[] inputs = sc.nextLine().split(" ");
            int n = Integer.parseInt(inputs[0]);
            int m = Integer.parseInt(inputs[1]);
            nSum(n, m);
        }
    }
}