LinkedList实现
public class LinkedList<E> {
private class Node{
public E e;
public Node next;
public Node(E e, Node next){
this.e = e;
this.next = next;
}
public Node(E e){
this(e, null);
}
public Node(){
this(null, null);
}
@Override
public String toString(){
return e.toString();
}
}
private Node dummyHead;
private int size;
public LinkedList(){
dummyHead = new Node();
size = 0;
}
// 获取链表中的元素个数
public int getSize(){
return size;
}
// 返回链表是否为空
public boolean isEmpty(){
return size == 0;
}
// 在链表的index(0-based)位置添加新的元素e
// 在链表中不是一个常用的操作，练习用：）
public void add(int index, E e){
if(index < 0 || index > size)
throw new IllegalArgumentException("Add failed. Illegal index.");
Node prev = dummyHead;
for(int i = 0 ; i < index ; i ++)
prev = prev.next;
prev.next = new Node(e, prev.next);
size ++;
}
// 在链表头添加新的元素e
public void addFirst(E e){
add(0, e);
}
// 在链表末尾添加新的元素e
public void addLast(E e){
add(size, e);
}
// 获得链表的第index(0-based)个位置的元素
// 在链表中不是一个常用的操作，练习用：）
public E get(int index){
if(index < 0 || index >= size)
throw new IllegalArgumentException("Get failed. Illegal index.");
Node cur = dummyHead.next;
for(int i = 0 ; i < index ; i ++)
cur = cur.next;
return cur.e;
}
// 获得链表的第一个元素
public E getFirst(){
return get(0);
}
// 获得链表的最后一个元素
public E getLast(){
return get(size - 1);
}
// 修改链表的第index(0-based)个位置的元素为e
// 在链表中不是一个常用的操作，练习用：）
public void set(int index, E e){
if(index < 0 || index >= size)
throw new IllegalArgumentException("Set failed. Illegal index.");
Node cur = dummyHead.next;
for(int i = 0 ; i < index ; i ++)
cur = cur.next;
cur.e = e;
}
// 查找链表中是否有元素e
public boolean contains(E e){
Node cur = dummyHead.next;
while(cur != null){
if(cur.e.equals(e))
return true;
cur = cur.next;
}
return false;
}
// 从链表中删除index(0-based)位置的元素, 返回删除的元素
// 在链表中不是一个常用的操作，练习用：）
public E remove(int index){
if(index < 0 || index >= size)
throw new IllegalArgumentException("Remove failed. Index is illegal.");
Node prev = dummyHead;
for(int i = 0 ; i < index ; i ++)
prev = prev.next;
Node retNode = prev.next;
prev.next = retNode.next;
retNode.next = null;
size --;
return retNode.e;
}
// 从链表中删除第一个元素, 返回删除的元素
public E removeFirst(){
return remove(0);
}
// 从链表中删除最后一个元素, 返回删除的元素
public E removeLast(){
return remove(size - 1);
}
// 从链表中删除元素e
public void removeElement(E e){
Node prev = dummyHead;
while(prev.next != null){
if(prev.next.e.equals(e))
break;
prev = prev.next;
}
if(prev.next != null){
Node delNode = prev.next;
prev.next = delNode.next;
delNode.next = null;
size --;
}
}
@Override
public String toString(){
StringBuilder res = new StringBuilder();
Node cur = dummyHead.next;
while(cur != null){
res.append(cur + "->");
cur = cur.next;
}
res.append("NULL");
return res.toString();
}
}
LinkedListSet实现
Set接口
public interface Set<E> {
void add(E e);
boolean contains(E e);
void remove(E e);
int getSize();
boolean isEmpty();
}
public class LinkedListSet<E> implements Set<E> {
private LinkedList<E> list;
public LinkedListSet(){
list = new LinkedList<>();
}
@Override
public int getSize(){
return list.getSize();
}
@Override
public boolean isEmpty(){
return list.isEmpty();
}
@Override
public void add(E e){
if(!list.contains(e))
list.addFirst(e);
}
@Override
public boolean contains(E e){
return list.contains(e);
}
@Override
public void remove(E e){
list.removeElement(e);
}
}
LinkedListMap实现
Map接口
public interface Map<K, V> {
void add(K key, V value);
V remove(K key);
boolean contains(K key);
V get(K key);
void set(K key, V newValue);
int getSize();
boolean isEmpty();
}
public class LinkedListMap<K, V> implements Map<K, V> {
private class Node {
public K key;
public V value;
public Node next;
public Node(K key, V value, Node next) {
this.key = key;
this.value = value;
this.next = next;
}
public Node(K key) {
this(key, null, null);
}
public Node() {
this(null, null, null);
}
@Override
public String toString() {
return key.toString() + " : " + value.toString();
}
}
private Node dummyHead;
private int size;
public LinkedListMap() {
dummyHead = new Node();
size = 0;
}
// 获取链表中的元素个数
@Override
public int getSize() {
return size;
}
// 返回链表是否为空
@Override
public boolean isEmpty() {
return size == 0;
}
private Node getNode(K key) {
Node current = dummyHead.next;
while (current != null) {
if (current.key.equals(key)) {
return current;
}
current = current.next;
}
return null;
}
@Override
public void put(K key, V value) {
Node node = getNode(key);
if (node == null) {
dummyHead.next = new Node(key, value, dummyHead.next);
size++;
} else {
node.value = value;
}
}
@Override
public V remove(K key) {
Node prev = dummyHead;
while (prev.next != null) {
Node cur = prev.next;
if (cur.key.equals(key)) {
prev.next = cur.next;
cur.next = null;
size--;
return cur.value;
}
}
return null;
}
// 查找链表中是否有元素e
@Override
public boolean contains(K key) {
return getNode(key) != null;
}
@Override
public V get(K key) {
Node node = getNode(key);
return node == null ? null : node.value;
}
@Override
public void set(K key, V newValue) {
Node node = getNode(key);
if (node == null)
throw new IllegalArgumentException("key doesn't exist");
node.value = newValue;
}
}
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