ArrayList由数组实现:
public class myArrayList {
private Object[] element;
private int size;
public myArrayList(int initCapacity) {
if (initCapacity < 0) {
throw new IllegalArgumentException("Illegal Capacity:" + initCapacity);
}
element = new Object[initCapacity];
}
public myArrayList() {
this(10);
}
public boolean add(Object obj) {
if (size >= element.length) {
Object[] biggerlist = new Object[size * 2 + 1];
System.arraycopy(element, 0, biggerlist, 0, element.length);
element = biggerlist;
}
element[size++] = obj;
return true;
}
public boolean isEmpty() {
return size == 0;
}
public Object get(int index) throws Exception {
rangeChack(index);
return element[index];
}
public boolean remove(int index) throws Exception {
rangeChack(index);
int numMoved = size - index - 1;
if (numMoved > 0) {
System.arraycopy(element, index + 1, element, index, numMoved);
}
return true;
}
private void rangeChack(int index) throws Exception {
if (index < 0 || index >= size) {
throw new Exception("Out of index");
}
}
public static void main(String[] args) throws Exception {
myArrayList list = new myArrayList();
list.add("www");
System.out.println(list.isEmpty());
System.out.println(list.get(0));
}
}
LinekdList(双向链表)由节点类连接实现
Node类:
public class Node {
public Node() {
super();
this.previous = null;
this.obj = null;
this.next = null;
}
Node previous;
Object obj;
Node next;
public Node(Node previous, Object obj, Node next) {
super();
this.previous = previous;
this.obj = obj;
this.next = next;
}
public Node getPrevious() {
return previous;
}
public void setPrevious(Node previous) {
this.previous = previous;
}
public Object getObj() {
return obj;
}
public void setObj(Object obj) {
this.obj = obj;
}
public Node getNext() {
return next;
}
public void setNext(Node next) {
this.next = next;
}
}
LinekdList(类):
public class myLInkedList {
private Node first;
private Node last;
private int size;
public void add(Object obj) {
Node node = new Node();
if (first == null) {
node.setPrevious(null);
node.setObj(obj);
node.setNext(null);
first = node;
last = node;
} else {
node.setPrevious(last);
node.setObj(obj);
node.setNext(null);
last.setNext(node);
last = node;
}
size++;
}
public int size() {
return size;
}
public Object get(int index) throws Exception {
rangeCheck(index);
Node tmp = first;
if (first == null) {
return null;
} else {
tmp = first;
for (int i = 0; i < index; i++) {
tmp = tmp.next;
}
}
return tmp.obj;
}
public void insert(int index, Object obj) throws Exception {
Node tmp = node(index);
Node newNode = new Node();
newNode.obj = obj;
if (tmp != null) {
Node pre = tmp.previous;
pre.next = newNode;
newNode.previous = pre;
newNode.next = tmp;
tmp.previous = newNode;
}
}
public void remove(int index) throws Exception {
Node tmp = node(index);
Node pre = tmp.previous;
Node next = tmp.next;
pre.next = next;
next.previous = pre;
size--;
}
private Node node(int index) throws Exception {
rangeCheck(index);
Node tmp = first;
if (first == null) {
return null;
} else {
tmp = first;
for (int i = 0; i < index; i++) {
tmp = tmp.next;
}
}
return tmp;
}
private void rangeCheck(int index) throws Exception {
if (index < 0 || index >= size) {
throw new Exception("Out of index");
}
}
public static void main(String[] args) throws Exception {
myLInkedList list = new myLInkedList();
list.add("qq");
list.add("dd");
list.add("ff");
list.add("hh");
System.out.println(list.get(2));
list.remove(2);
System.out.println(list.get(2));
}
}