title: Most efficient way to remove duplicate elements from a list
body: <p>I have an unsorted list, from which I want to remove duplicates. What is the most efficient to perform this in C. In my case, the list is a linked list of arrays. In other words several arrays linked together. Duplicates can only happen in different arrays. So for example there can't be a duplicate inside array 1, but the same number can be found in array 1 and 2.</p>