手工实现LinkedList3_remove移除节点_getNode方法

手工实现LinkedList3_remove移除节点_getNode方法

public class SxtLinkedList03 {
	private Node first;
	private Node last;
	private int size;
	public void add(Object obj) {
		Node n1 = new Node(obj);
		if(first==null) {
			first=n1;
			last=n1;
		}else {
			n1.previous=last;
			last.next=n1;
			n1.next=null;
			last=n1;
		}
		size++;
	}
	public String toString() {
		StringBuilder sb = new StringBuilder("[");
		Node temp = first;
		while(temp!=null) {
			sb.append(temp.element+",");
			temp=temp.next;
		}
		sb.setCharAt(sb.length()-1, ']');
		return sb.toString();
	}
	public Object get(int index) {
		if(index<0||index>size-1) {
			throw new RuntimeException("索引位置不合法:"+index);
		}
		Node temp=getNode(index);
		return temp.element;
	}
	public Node getNode(int index) {
		Node temp=null;
		if(index<=(size>>1)) {//size>>1除以2
			temp=first;
			for(int i=0;i<index;i++) {
				temp=temp.next;
			}
		}else if(index>(size>>1)) {
			temp=last;
			for(int i =size-1;i>index;i--) {
				temp=temp.previous;
			}
		}
		return temp;
	}
	public void remove(int index) {
		Node temp = getNode(index);
		if(temp!=null) {
		Node up = temp.previous;
		Node down = temp.next;
		if(up!=null) {
		up.next=down;
		}
		if(down!=null) {
		down.previous=up;
		}
		if(index==0) {
			first = down;
		}
		if(index==size-1) {
			last=up;
		}
		}
		size--;
	}
	public static void main(String[] args) {
		SxtLinkedList03 s3 = new SxtLinkedList03();
		s3.add("阿狸");
		s3.add("卡莎");
		s3.add("阿卡丽");
		System.out.println(s3);
		System.out.println(s3.get(0));
		s3.remove(1);
		System.out.println(s3);
		s3.remove(0);
		System.out.println(s3);
	}
}

效果