When I was a student, it was easy to remember when holidays were coming. Now that I’m working since more than a decade, it’s harder to remember and distinguish those period sometimes! That said, I have to say that the pace at work is different and this is how I remember that I should take some days off.
In December 2016, I started to write a PHP library called PHPermutations to handle permutations and combinations of an array of items. The array items can be any type of object: integers, arrays, strings or objects, the library will still continue to work without any trouble. But before going further, let me remind you what are the differences between permutations and combinations.