LINKED LISTS EXAMPLES Salim Malakouti Linked List? 523 Pointer Node ValuePointer Node Class public class Node { /** * Data */ private T value; /** * Pointer to the next Node */ private Node next; public Node(T value, Node next) { this.setValue(value); this.setNext(next); } } Comprehension Questions Question 1 If we just want to iterate over the list and print all values, which one is faster why? Array Linked List? Answer Array Because all elements are beside each other. There is no need for scanning the file. Algorithmic Questions How to add a new value to the list? Question 1 /** * This function simply adds a new node to the list by adding it to the * beginning. * value */ public void add(T value) { Node tmp = getHead(); setHead(new Node(value)); getHead().setNext(tmp); } How to clear the Linked List? Question 2 Clear /** * This function simply clears the list */ public void clear() { setHead(null); } How to find the size? Question 3 Size /** * Computes the size of the list. * */ public int size() { Node current = getHead(); int size = 0; while (current != null) { current = current.getNext(); size++; } return size; } Size Recursive /** * Computes the size of the list but using a recursive function. * */ public int sizeRecursive() { return sizeR(head); } /** * The inner part of the recursive size head */ private int sizeR(Node head) { if (head == null) return 0; else return sizeR(head.getNext()) + 1; } How to get the last value? Question 4 Get Tail /** * This function returns the last element. * */ public Node getTail() { Node current = getHead(); while (current.getNext() != null) { current = current.getNext(); } return current; } Get Tail Recursive public Node getTailRecursive() { return tailR(head); } /** * Inner function for finding tail recursively node */ private Node tailR(Node node) { if (node.getNext() == null) return node; return tailR(node.getNext()); } How to append to lists? Question 5 Append /** * Append the input list to the end of this list. * l */ public void append(LinkedList l) { Node tail = getTail(); if (tail == null) { head = l.getHead(); } else { tail.setNext(l.getHead()); } How to check if a specific value is in the list? Question 6 Has Value /** * This function checks to see if there is a node with value equal to the * input. * value */ public boolean hasValue(T value) { Node current = getHead(); while (current != null) { if (current.getValue().equals(value)) { return true; } current = current.getNext(); } return false; } How to find the ith element? Question 7 Get ith /** * This function returns the ith item in the list. */ public T get(int index) { Node current = getHead(); int i = 0; while (current != null) { if (i == index) return current.getValue(); current = current.getNext(); i++; } return null; } How to remove a specific element? Question 8 Remove /** * This functions removes nodes in the list equal to the input. Only one at * a time. * value */ public void remove(T value) { Node pre = null; Node current = getHead(); while (current != null) { if (current.getValue().equals(value)) { if (pre != null) { pre.setNext(current.getNext()); } else { setHead(current.getNext()); } break; } pre = current; current = current.getNext(); } How to reverse the list? Question 9 Reverse /** * This function simply reverses the list */ public void reverse() { Node next = getHead(); Node pre = null; Node tmp = null; while (next != null) { tmp = next; next = next.getNext(); tmp.setNext(pre); pre = tmp; } setHead(tmp); } How to insert in ith position? Question 10 Insert in ith position public void insert(int index, T value) { Node current = getHead(); Node pre = null; int i = 0; while (current != null) { if (i == index) { if (pre != null) { pre.setNext(new Node(value, current)); } else { setHead(new Node(value, current)); } pre = current; current = current.getNext(); i++; }