## Description

Introduction

In mathematics, the notion of permutation relates to the act of rearranging, or permuting, all

the members of a list into some sequence or order. For example, there are six permutations of the

list [1,2,3], namely: [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1]. The number

of permutations of n distinct objects is n factorial (n!).

What to do

Implement the recursive method named permutation (marked TO DO) which can be found in

Permutation.java. This method takes an ArrayList