链表 最基本插入删除查找

java 代码如下：

package algorithm;

public class LinkedList {
	
	private class Data {
		public Object obj;
		public Data next;
		public Data(Object obj) {
			this.obj = obj;
			next = null;
		}
	}
	
	private Data first=null;
	
	/**
	 * 头插法
	 */
	public void insert(Object obj) {
		if(first == null) {
			first = new Data(obj);
		} else{
			Data newNode = new Data(obj);
			newNode.next = first ;
			first = newNode;
		}
		
	}
	/**
	 * 
	 * @param obj
	 */
	public void delete(Object obj) {
		if(first==null)
			return;
		Data beforeNeedDel = first;
		Data needDel = first;
		
		while(needDel!=null) {
			if(beforeNeedDel==needDel && needDel.obj.equals(obj)) {
				first = first.next;
				beforeNeedDel = first;
				needDel = first;
			} else if(beforeNeedDel==needDel && !needDel.obj.equals(obj)){
				needDel = needDel.next;
			} else if(beforeNeedDel!=needDel && needDel.obj.equals(obj)){
				needDel = needDel.next;
				beforeNeedDel.next = needDel;
			} else if(beforeNeedDel!=needDel && !needDel.obj.equals(obj)){
				needDel = needDel.next;
				beforeNeedDel = beforeNeedDel.next;
			}
			
		}
	}
	/**
	 * 
	 * @param obj
	 */
	public Data find(Object obj) {
		Data needFind = first;
		while(needFind!=null) {
			if(needFind.obj.equals(obj)) {
				return needFind;
			} 
			needFind = needFind.next;
		}
		return null;
	}
	
	public void display() {
		Data displayNode = first;
		while(displayNode!=null) {
			System.out.print(displayNode.obj+"——>");
			displayNode = displayNode.next;
		}
	}
	
	
	
	public static void main(String[] args) {
		LinkedList linkList = new LinkedList();
		linkList.insert("3");
		linkList.insert("2");
		linkList.insert("3");
		linkList.insert("4");
		linkList.insert("5");
		linkList.insert("3");
		linkList.insert("3");
		linkList.display();
		System.out.println(linkList.find("3"));
		linkList.delete("3");
		linkList.display();
	}
}