An array of methods to re---hash

hash method I've found Baidu, often with good speed and performance, this article is mainly a step by step process to explain hash method ( in fact, not many steps )

Here we can see each custom index is unique, in fact, equivalent to the weight of the array arr already

 The rest we need to custom index to be extracted on a new array

Code to such a point, it's that simple, two-step purpose is to simply explain to re-process.