2014
04-09

# Star Gazer

Sven Cal Payang is a Natural who was a member of the Phantom Pain Special Forces and piloted the GAT-X105E Strike Noir.
As is known, Sven was astronomy amateur when he was still a child. After the war between ZAFT and Earth Alliance, he decided to continue his childhood dream.
Sven’s new house is located at a peaceful town. What’s more, there is a lake in his garden. One day, he came up with a new idea on finding stars using interference phenomenon. He put a radio wave receiver h meter above the surface of a lake. When a radio star rising, it detects maxima successively due to interference of radio waves from the star, and its reflection waves from the water. The wavelength of the waves is λ centimeters. Sven wants to find stars as quickly as possible. Can you help him?

Several cases are given until the end of input. Each line contains h and λ separated by a space.

Several cases are given until the end of input. Each line contains h and λ separated by a space.

0.5 20.0
20.0 0.5

5.74
0.00
Hint

Notice: When light reflected from a medium having an index of refraction greater than that of the medium in which it is traveling, a 180°phase change (or λ/2 shift ) occurs.

/*
说起这题真的会气死人的，物理到现在全忘了，什么叫干涉完全不知道，等于说这题根本没办法解
看了解题报告才知道，悲剧！！看来做ACM什么都要学好啊，上回也有一个物理的要积分的题目
*/
#include <iostream>
#include <cstdio>
#include <cmath>
#define IP 3.1415926
using namespace std;
int main()
{
double r, h;
while( scanf("%lf %lf", &h, &r) != EOF)
{
double ans = asin(0.01 * r / (4 * h));
printf("%0.2lf/n", 180 * ans / IP);
}
}

1. 制裁华为的后果？我只能说，好样的，就是这样。哈哈哈，虽然国产的手机比不上苹果，但是又怎么样？为毛苹果在中国卖的最贵？果狗们这是你们的功劳，你们继续捧你们的美国爹。

2. 3，求得所有的为的总和sum—->所有数的总和
printf( "Not Possible" );—->printf("impossible");
对吗？

3. 思路二可以用一个长度为k的队列来实现，入队后判断下队尾元素的next指针是否为空，若为空，则出队指针即为所求。