Skip to main content

How to remove duplicates from a LinkedList in Kotlin

How to remove duplicates from a LinkedList in Kotlin.

Here's a step-by-step tutorial on how to remove duplicates from a LinkedList in Kotlin:

Step 1: Create a Kotlin LinkedList​

First, we need to create a LinkedList in Kotlin. You can create an empty LinkedList or initialize it with some elements. Here's an example of creating a LinkedList:

val linkedList = LinkedList<Int>()

Step 2: Add elements to the LinkedList​

To demonstrate the removal of duplicates, let's add some elements to the LinkedList. You can add elements using the add method. Here's an example of adding elements to the LinkedList:

linkedList.add(1)
linkedList.add(2)
linkedList.add(3)
linkedList.add(2)
linkedList.add(4)

Step 3: Create a HashSet​

To remove duplicates from the LinkedList, we can use a HashSet. A HashSet is a collection that does not allow duplicate elements. We will iterate over the LinkedList and add its elements to the HashSet.

val set = HashSet<Int>()

Step 4: Iterate over the LinkedList and add elements to the HashSet​

Now, we will iterate over the LinkedList using a for-each loop and add its elements to the HashSet. This will automatically remove any duplicates.

for (element in linkedList) {
    set.add(element)
}

Step 5: Clear the LinkedList​

After removing the duplicates, we need to clear the original LinkedList.

linkedList.clear()

Step 6: Add unique elements back to the LinkedList​

Finally, we will add the unique elements from the HashSet back to the LinkedList.

for (element in set) {
    linkedList.add(element)
}

Step 7: Complete code example​

Here's the complete code example that removes duplicates from a LinkedList in Kotlin:

import java.util.LinkedList
import java.util.HashSet

fun main() {
    val linkedList = LinkedList<Int>()
    linkedList.add(1)
    linkedList.add(2)
    linkedList.add(3)
    linkedList.add(2)
    linkedList.add(4)

    val set = HashSet<Int>()

    for (element in linkedList) {
        set.add(element)
    }

    linkedList.clear()

    for (element in set) {
        linkedList.add(element)
    }

    println("LinkedList after removing duplicates: $linkedList")
}

That's it! You have successfully removed duplicates from a LinkedList in Kotlin.