1753. Bookshelf.java

import java.util.Scanner;

import static java.lang.Math.*;




public class Bookshelf {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int h = sc.nextInt();
        int H = sc.nextInt();
        int L = sc.nextInt();


        double x   = sqrt(pow(h, 4.0/3.0) * pow(H, 2.0/3.0)/pow(2, 2.0/3.0) - pow(h, 2.0));
        double res = H/2.0*1/sqrt(1 + pow(h/x, 2.0)) - x;
        if (res <= L && res > 0)
            System.out.format("%.6f", res);
        else
            System.out.format("%.6f", 0.0);

    }
}