public class LinkList<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 LinkList() { dummyHead = new Node(null, null); size = 0; } //获取链表元素个数 public int getSize() { return size; } //链表是否为空 public boolean isEmpty() { return size == 0; } //增加链表头元素 public void addFirst(E e) { // Node node = new Node(e); // node.next = head; // head = node; add(0, e); } //增加链表元素个数 public void add(int index, E e) { if (index < 0 || index > size) { throw new IllegalArgumentException("index < 0 or index > size,add is fail."); } Node prev = dummyHead; for (int i = 0; i < index; i++) { prev = prev.next; } // Node node = new Node(e); // node.next = prev.next; // prev.next = node; prev.next = new Node(e, prev.next); size++; } //添加链表末尾元素 public void addLast(E e) { add(size, e); } //获取元素index public E get(int index) { if (index < 0 || index >= size) { throw new IllegalArgumentException("get is fail,index < 0 or index > size"); } Node cur = dummyHead.next; for (int i = 0;i < index;++i) { cur = cur.next; } return cur.e; } //获取第一个元素 public E getFirst() { return get(0); } //获取最后一个元素 public E getLast() { return get(size - 1); } //判读是否包含 public boolean contains(E e) { Node cur = dummyHead.next; while (cur != null) { if (cur.e.equals(e)) { return true; } cur = cur.next; } return false; } //修改值 public void set(int index,E e) { if (index < 0 || index >= size) { throw new IllegalArgumentException("set is fail,index < 0 or index > size"); } Node cur = dummyHead.next; for (int i = 0;i < index;++i) { cur = cur.next; } cur.e = e; } //删除元素 public E remove(int index) { if (index < 0 || index >= size) { } Node prev = dummyHead; for (int i = 0;i < index;++i) { prev = prev.next; } //删除的元素 Node retNode = prev.next; prev.next = retNode.next; retNode.next = null;//删除元素的指向下一个地址为空 size-- ; return retNode.e; } //删除第一元素 public E removeFirst() { return remove(0); } //删除最后一个元素 public E removeLast() { return remove(size - 1); } @Override public String toString() { StringBuilder res = new StringBuilder(""); for (Node cur = dummyHead.next; cur != null; cur = cur.next) { res.append(cur + "->"); } res.append("NULL"); return res.toString(); } }
用链表实现栈
public class LinkListStack<E> implements Stack<E> { private LinkList<E> linkList; public LinkListStack() { linkList = new LinkList<>(); } @Override public int getSize() { return linkList.getSize(); } @Override public boolean isEmpty() { return linkList.isEmpty(); } @Override public void push(E e) { linkList.addFirst(e); } @Override public E pop() { return linkList.removeFirst(); } @Override public E peek() { return linkList.getFirst(); } @Override public String toString() { StringBuilder res = new StringBuilder(); res.append("Stack top["); res.append(linkList); res.append("] tail"); return res.toString(); } }