计算13号星期五的未来事件再度发生 [英] Calculating future occurences of Friday the 13th

问题描述

我希望能够开始一年的时间，并计算出现黑色星期五的。蛮力解决方案是很容易和明显。我有一些稍微好一点，但我毫不怀疑，有人能拿出一个优雅的算法这一点。

I'd like to be able to start with a year, and calculate occurrences of Friday the 13th. A brute force solution is easy and obvious. I have something slightly better, but I have no doubt that someone else can come up with an elegant algorithm for this.

也许有点麻烦，我很想在提供程序一个月，并将其找到明年在该月有一个周五的第13位。

Perhaps a little trickier, I'd be interested in giving the program a month, and have it find the next year in which that month has a Friday the 13th.

随意使用伪$​​ C $ C，但我希望人们会投更多的工作code样品中，你最喜欢的语言。

Feel free to use pseudo code, but I expect people will vote more for working code samples in you favorite language.

推荐答案

任何一个月，与周日开始有一个周五的第十三位。目前只有14的组合可能知道何日今年第一是（带或不带闰年，和太阳-SAT）。你应该只计算一次，并结束它。你只检查14 * 12个月可能开始用，很好用的原因。

Any month that starts with a Sunday has a Friday on the thirteenth. There are only 14 combinations possible knowing what day the first of the year is on (with or without leap year, and sun-sat). You should just calculate it once and get it over with. You'd only check 14*12 possible months to start out with, well with in reason.

产生的表元素（从2009年，2010年）：

resultant table element (from 2009, 2010):

[Thursday,false] => Feb, March, Nov
[Friday,false] => Aug

填写表格，你有一个通用的月月（31），二月（28）..然后用迭代一周的每一天的种子，并指出月份开始的周日，也有一个闰年没有。 pretty的直线前进，一旦完成，你可以与我们分享：）

to fill the table you have a generic month Jan(31),Feb(28).. and then iterate with a seed of each day of the week, noting months that start with sunday, and also with a leap year and without. Pretty straight forward, and once done, you can share it with us :)

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