linkedlist.md

LinkedList

Java

• List has a specified order and provides indexed access to them
• ArrayList is an implementation of List, has order for sure, based on the index.
• LinkedList is a doubly-linked List, and is an implementation of List as well, ordered.
  • it has a Node class managing the order, which has previous and next reference, but invisible to outside

private static class Node<E> {
    E item;
    Node<E> next;
    Node<E> prev;

    Node(Node<E> prev, E element, Node<E> next) {
        this.item = element;
        this.next = next;
        this.prev = prev;
    }
}

Kotlin

• listOf(), immutable, when it's empty, it is an EmptyList, which is an implementation of List
• listOf(1, 2, 3), when it has elements, it is an ArrayList, but immutable!
• arrayListOf(), it's simply an Java ArrayList, mutable!

Code example

Go

Ha, Golang does not have while keyword, but use for instead:

for head.Next != nil {
    n = head.Next
    head.Next = p
    p = head
    head = n
}