题解 | #求小球落地5次后所经历的路程和第5次反弹的高度#

import java.util.*;
import java.math.*;

public class Main {
	//计算除法
    public static double divDouble(double m1, double m2) {
        BigDecimal p1 = new BigDecimal(Double.toString(m1));
        BigDecimal p2 = new BigDecimal(Double.toString(m2));
        return p1.divide(p2).doubleValue();
    }
    //计算乘法
    public static double multiplyDouble(double m1, double m2) {
        BigDecimal p1 = new BigDecimal(Double.toString(m1));
        BigDecimal p2 = new BigDecimal(Double.toString(m2));
        return p1.multiply(p2).doubleValue();
    }
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        while (sc.hasNextInt()) {
            int first = sc.nextInt();
            double hight = multiplyDouble(first, 1.0);
            double sum = hight;
            double five = 0;
            
        	//模拟5次反弹
            for (int i=0; i<4; i++) {
                hight = divDouble(hight, 2.0);
                sum = sum + multiplyDouble(hight, 2.0);
            }
        
        //输出总和，再计算一次反弹才是第五次高度
        System.out.println(sum);
        System.out.println(divDouble(hight, 2.0));
        }
        
    }
}