一道C语言编程比赛题（时钟追赶问题）

问题描述：

The three hands of the clock are rotating every second and meeting each other many times everyday. Finally, they get bored of this and each of them would like to stay away from the other two. A hand is happy if it is at least D degrees from any of the rest. You are to calculate how much time in a day that all the hands are happy.

大概的意思是：任意给一个角度，求出时钟上的秒分时指针之间的角度大于等于这个角度的概率。

解决的方案如下：

/*************************************************************************
	> File Name: clock.c
	> Author: Baniel Gao
	> Mail: createchance@163.com 
	> Blog: blog.youkuaiyun.com/createchance 
	> Created Time: Tue 08 Apr 2014 05:23:27 PM CST
 ************************************************************************/
#include <stdio.h>

#define HALF_DAY	43200
#define SEC_RATE	6
#define MIN_RATE	(1.0/10)
#define HOUR_RATE	(1.0/120)

void happy_times(double degrees);
sta