手工实现LinkedList2_get查询_节点遍历

手工实现LinkedList2_get查询_节点遍历

public class SxtLinkedList02 {
	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) {
		Node temp=null;
		if(index<0||index>size-1) {
			throw new RuntimeException("索引位置不合法:"+index);
		}
		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.element;
	}
	public static void main(String[] args) {
		SxtLinkedList02 s2 = new SxtLinkedList02();
		s2.add("阿狸");
		s2.add("卡莎");
		s2.add("阿卡丽");
		System.out.println(s2);
		System.out.println(s2.get(0));
	}
}

效果