package DataStructure;

/**
 * @author: Inki
 * @email: inki.yinji@qq.com
 * @create: 2020 1024
 * @last_modify: 2020 1025
 */

public class MySingleLinkedList <AnyType> {

 /**
 * Only used to store the head node.
 */
 private SingleNode<AnyType> head = new SingleNode(new Object());

 /**
 * The single linked list current size.
 */
 private int size = 0;

 /**
 * Add element to the end of the list.
 * @param:
 * paraVal: The given value.
 */
 public void add(AnyType paraVal) {
 insert(size, paraVal);
 }//Of add

 /**
 * Pop the last element.
 * @return:
 * The popped value.
 */
 public AnyType pop(){
 return delete(size - 1);
 }//Of pop

 /**
 * Insert element at specified index.
 * @param:
 * paraIdx: The given index.
 * paraVal: The given value.
 */
 public void insert(int paraIdx, AnyType paraVal) {

 if (paraIdx > size) {
  throw new IndexOutOfBoundsException("The index error.");
 }//Of if

 SingleNode <AnyType> tempNode = head;
 int i = 0;
 while (i++ < paraIdx) {
  tempNode = tempNode.next;
 }//Of while

 SingleNode<AnyType> paraNode = new SingleNode <>(paraVal);
 paraNode.next = tempNode.next;
 tempNode.next = paraNode;
 size++;
 }//of add

 /**
 * Delete the element at specified index.
 * @param:
 * paraIdx: The given index of element to delete.
 * @return:
 * The deleted value.
 */
 public AnyType delete(int paraIdx) {
 if (size == 0) {
  throw new RuntimeException("The single linked list is empty.");
 }//Of if

 if (size <= paraIdx) {
  throw new IndexOutOfBoundsException("The index error.");
 }//Of if

 SingleNode <AnyType> retNode = head;
 int i = 0;
 while (i++ < paraIdx) {
  retNode = retNode.next;
 }//Of while

 retNode.next = retNode.next.next;

 size--;
 return retNode.val;
 }//Of delete

 /**
 * Get the current size of the single linked list.
 * @return:
 * The current size of the single linked list.
 */
 public int getSize() {
 return size;
 }//Of getSize

 /**
 * Display the single linked list.
 */
 public void display() {
 if (size == 0) {
 throw new RuntimeException("The single linked list is empty.");
 }//Of if
 
 System.out.print("The single linked list is:\n[");
 SingleNode <AnyType> tempNode = head;
 int i = 0;
 while (i++ < size - 1) {
  tempNode = tempNode.next;
  System.out.printf("%s, ", tempNode.val);
 }//Of while
 System.out.printf("%s]\n", tempNode.next.val);
 }//Of display

 /**
 * The main function.
 */
 public static void main(String[] args) {
 MySingleLinkedList <Character> test = new MySingleLinkedList<>();
 test.add('a');
 test.add('b');
 test.insert(0, 'c');
 test.add('d');
 test.insert(0, '5');
 test.delete(4);
 test.pop();
 test.add('+');
 test.display();
 System.out.println(test.getSize());
 }//Of main

}//Of class MySingleLinkedList

class SingleNode <AnyType>{

 /**
 * The value.
 */
 AnyType val;

 /**
 * The next node.
 */
 SingleNode<AnyType> next;

 /**
 * The first constructor.
 * @param
 * paraVal: The given value.
 */
 SingleNode (AnyType paraVal) {
 val = paraVal;
 }//The first constructor

}//Of class SingleNode