Question

Suppose you have a List. Write a generic static method deduplicate that modifies the list in-place, removing all but one of any element that the list contains, and leaving the list otherwise unchanged - specifically, do not change its order! Items are considered duplicates according to the semantics of their equals method. For example, the after deduplication, the list [3, 1, 2, 1, 3, 4] would be changed to [3, 1, 2, 4].

Answer 1

The question requires the creation of a generic static method called deduplicate to remove duplicate elements from a list in a programming language like Java without changing the list's order. A HashSet can be used to track seen elements while iterating over the list for efficient deduplication.

Step-by-step explanation:

The question pertains to writing a generic static method in a programming context which involves manipulating a List data structure. To address the question, you must create a method called deduplicate that takes a list as its parameter and removes any duplicate elements without altering the order of the remaining items.

This task can be accomplished by iterating over the list and using a HashSet or similar data structure to track already seen elements.

A sample method in Java might look like:

public static void deduplicate(List list) {
Set seen = new HashSet<>();
Iterator it = list.iterator();
while (it.hasNext()) {
T element = it.next();
if (!seen.add(element)) {
it.remove();
}
}
}

In this method, HashSet is used to keep track of the elements that have already been encountered. If an element is already in the set, it means it is a duplicate and should be removed from the list.