参考文献
指针
将某个变量赋值给指针,实际上就是将这个变量的地址赋值给指针,或者反过来说,指针存储了这个变量的内存地址,指向了这个变量,通过指针就能找到这个变量.
p->next=q: p结点中的next指针存储了q结点的内存地址.
链表
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| package com.holelin.linkedlist;
public class LinkedList<E> {
private Node dummyHead;
private int size;
public LinkedList() { dummyHead = new Node(null, null); size = 0; }
public void add(E data, int index) { if (index < 0 || index > size) { throw new IllegalArgumentException("Add failed .Illeal index."); }
Node prev = dummyHead; for (int i = 0; i < index; i++) { prev = prev.next; } prev.next = new Node(data, prev.next); size++;
}
public void addFirst(E data) { add(data, 0); }
public void addLast(E data) { add(data, size); }
public int getSize() { return size; }
public boolean isEmpty() { return size == 0; }
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.data; }
public E getFirst() { return get(0); }
public E getLast() { return get(size - 1); }
public void set(E data, int index) { 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.data = data; }
public boolean contains(E data) { Node cur = dummyHead.next; while (cur != null) { if (cur.data.equals(data)) { return true; } cur = cur.next; } return false; }
public E remove(int index) { if (index < 0 || index > size) { throw new IllegalArgumentException("Remove failed. Illegal index."); } Node prev = dummyHead; for (int i = 0; i < index; i++) { prev = prev.next; } Node delNode = prev.next; prev.next = delNode.next; delNode.next = null; size--; return delNode.data; }
public E removeFirst() { return remove(0); }
public E removeLast() { return remove(size - 1); }
public void removeElement(E e) { Node prev = dummyHead; while (prev.next != null) { if (prev.next.data.equals(e)) { break; } prev = prev.next; } if (prev.next != null) { Node delNode = prev.next; prev.next = delNode.next; delNode.next = null; } }
@Override public String toString() {
StringBuilder res = new StringBuilder(); Node cur = dummyHead.next; while (cur != null) { res.append(cur).append("->"); cur = cur.next; } res.append("NULL"); return res.toString(); }
private class Node {
E data;
Node next;
public Node(E data, Node next) { this.data = data; this.next = next; }
public Node(E data) { this.data = data; this.next = null; }
public Node() { this(null, null); }
@Override public String toString() { return data.toString(); } } }
|
测试用例
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| package com.holelin.linkedlist;
public class LinkedListTest { public static void main(String[] args) { LinkedList<Integer> linkedList = new LinkedList<>(); for (int i = 0; i < 20; i++) { linkedList.addFirst(i); System.out.println(linkedList); } linkedList.add(99, 3); System.out.println(linkedList);
linkedList.remove(3); System.out.println(linkedList); linkedList.removeFirst(); System.out.println(linkedList); linkedList.removeLast(); System.out.println(linkedList); } }
|
应用场景
LRU缓存淘汰算法