10781 - Global Positioning System

medv · Post by **medv** » Thu Jan 06, 2005 5:56 pm

How to solve this problem?
Can smb give me some hints or articles to read?

Cho · Post by **Cho** » Thu Jan 06, 2005 7:38 pm

I really doubt whether you can get any hint since there are only six submissions in total and only one got AC. And I also doubt that whether this problem is well-defined.

Because from my understanding, the sunrise-sunset-time should consist of two pairs of date and time. However, the input contains only one date. For example, the time zone of Hong Kong is GMT+8:00. If the Hong Kong time of sunrise and sunset of 07/01 are 07:00 and 18:30, then the corresponding GMT time will be 23:00 of 06/01 and 10:30 of 07/01.

Destination Goa · Post by **Destination Goa** » Sat Feb 19, 2005 5:29 pm

1. Are times given in AM/PM or in 24 hours?
2. Does the Earth rotate around own axis in the same direction as it orbits the Sun or in the opposite?
3. Are there cases when sunrise happens a day before the sunset?

Destination Goa · Post by **Destination Goa** » Sat Feb 19, 2005 5:34 pm

<POSSIBLE SPOILER>

medv,

Day length over lattitude will grow and then it will decrease. So I think there are only two slices (inclined at angle of 23.45 to equator) with desired day length. If that's true, then sunrise/sunset values are needed only to find the hemisphere. Anyway, there is a great deal of possible precision errors.