class SinglyLinkedList<T> { Node<T> head; SinglyLinkedList(Node<T> head) { this.head = head; } public int size() { Node<T> node = head; int size = 1; while (node.next != null) { node = node.next; size++; } return size; } public int search(T data) { Node<T> node = head; int index = 0; while (node != null) { if (node.data.equals(data)) { return index; } node = node.next; index++; } return -1; } public String toString() { Node<T> node = head; StringBuilder strb = new StringBuilder(node.data.toString()); int i = 0; while (node.next != null && i++ < 99) { node = node.next; strb.append(',').append(node.data.toString()); } return strb.toString(); } public void reverse() { // TODO: consider what happens when there is only one node Node<T> previous = null; Node<T> current = head; Node<T> tmp; while (current != null) { tmp = current.next; current.next = previous; previous = current; current = tmp; } head = previous; } public T get(int n) { return getNode(n).data; } private Node<T> getNode(int n) { // TODO: handle out of range Node<T> node = head; for (int i = 1; i < n + 1; i++) { node = node.next; } return node; } public void insert(int index, T data) { Node<T> node = head; // TODO: hondle out of range for (int i = 1; i < index; i++) { node = node.next; } Node<T> newNode = new Node<>(data, node.next); node.next = newNode; } public void delete(int index) { // TODO: handle out of range and attempt to delete(0) when there is only one node Node<T> node = head; Node<T> previous = null; for (int i = 1; i < index + 1; i++) { previous = node; node = node.next; } if (previous != null) { previous.next = node.next; } else { head = node.next; } } public void swap(int first, int second) { Node<T> a = getNode(first); Node<T> b = getNode(second); Node<T> beforeA = null; if (first > 0) { beforeA = getNode(first - 1); } Node<T> beforeB = null; if (second > 0) { beforeB = getNode(second - 1); } if (beforeA != null) { beforeA.next = b; } if (beforeB != null) { beforeB.next = a; } Node<T> tmp = a.next; a.next = b.next; b.next = tmp; if (head == a) { head = b; } else if (head == b) { head = a; } } /* * A lot easier to swap data than nodes, but may be heavier */ public void swapData(int first, int second) { Node<T> firstNode = getNode(first); Node<T> secondNode = getNode(second); T tmp = firstNode.data; firstNode.data = secondNode.data; secondNode.data = tmp; } }

class Main { public static void main(String[] args) { SinglyLinkedList<String> sll = new SinglyLinkedList<>(new Node<>("foo", null)); sll.insert(1, "bar"); sll.insert(1, "brabra"); System.out.println(sll.size()); System.out.println(sll.search("bar")); System.out.println(sll.toString()); for (int i = 0; i < sll.size(); i++) { System.out.println(sll.get(i).toString()); } sll.reverse(); System.out.println("after reverse: " + sll.toString()); sll.swap(1, 2); System.out.println("after swap: " + sll.toString()); sll.swap(0, 1); System.out.println("after swap: " + sll.toString()); sll.delete(1); System.out.println("after delete(1): " + sll.toString()); sll.delete(0); System.out.println("after delete(0): " + sll.toString()); } }