I'm not familiar with these festivals but I assume that they follow a certain pattern (e.g. the second monday of January). If you know those "rules" then you should be able to write some code that calculates it for you.
"Any fool can write code that a computer can understand. Good programmers write code that humans can understand." --- Martin Fowler
Please correct my English.
yes , it is based on the certain rules and this rule is based on the full moon day of that particular month. The trick is to find the full moon the day which is the difficult part.I am not sure if there are any algorithms or logic
Yes, there is logic behind it. For example the phases of the moon repeat every 19 years. I would suggest you Google for epact, and how to calculate it.
