链表的原理及java实现代码示例

package com.zjn.LinkAndQueue;
/**
 * 自定义链表设计
 * 
 * @author zjn
 *
 */
public class MyLink {
	Node head = null;
	// 头节点
	/**
   * 链表中的节点，data代表节点的值，next是指向下一个节点的引用
   * 
   * @author zjn
   *
   */
	class Node {
		Node next = null;
		// 节点的引用，指向下一个节点
		int data;
		// 节点的对象，即内容
		public Node(int data) {
			this.data = data;
		}
	}
	/**
   * 向链表中插入数据
   * 
   * @param d
   */
	public void addNode(int d) {
		Node newNode = new Node(d);
		// 实例化一个节点
		if (head == null) {
			head = newNode;
			return;
		}
		Node tmp = head;
		while (tmp.next != null) {
			tmp = tmp.next;
		}
		tmp.next = newNode;
	}
	/**
   * 
   * @param index:删除第index个节点
   * @return
   */
	public Boolean deleteNode(int index) {
		if (index < 1 || index > length()) {
			return false;
		}
		if (index == 1) {
			head = head.next;
			return true;
		}
		int i = 1;
		Node preNode = head;
		Node curNode = preNode.next;
		while (curNode != null) {
			if (i == index) {
				preNode.next = curNode.next;
				return true;
			}
			preNode = curNode;
			curNode = curNode.next;
			i++;
		}
		return false;
	}
	/**
   * 
   * @return 返回节点长度
   */
	public int length() {
		int length = 0;
		Node tmp = head;
		while (tmp != null) {
			length++;
			tmp = tmp.next;
		}
		return length;
	}
	/**
   * 在不知道头指针的情况下删除指定节点
   * 
   * @param n
   * @return
   */
	public Boolean deleteNode11(Node n) {
		if (n == null || n.next == null)
		      return false;
		int tmp = n.data;
		n.data = n.next.data;
		n.next.data = tmp;
		n.next = n.next.next;
		System.out.println("删除成功！");
		return true;
	}
	public void printList() {
		Node tmp = head;
		while (tmp != null) {
			System.out.println(tmp.data);
			tmp = tmp.next;
		}
	}
	public static void main(String[] args) {
		MyLink list = new MyLink();
		list.addNode(5);
		list.addNode(3);
		list.addNode(1);
		list.addNode(2);
		list.addNode(55);
		list.addNode(36);
		System.out.println("linkLength:" + list.length());
		System.out.println("head.data:" + list.head.data);
		list.printList();
		list.deleteNode(4);
		System.out.println("After deleteNode(4):");
		list.printList();
	}
}

/**
   * 链表反转
   * 
   * @param head
   * @return
   */
  public Node ReverseIteratively(Node head) {
    Node pReversedHead = head;
    Node pNode = head;
    Node pPrev = null;
    while (pNode != null) {
      Node pNext = pNode.next;
      if (pNext == null) {
        pReversedHead = pNode;
      }
      pNode.next = pPrev;
      pPrev = pNode;
      pNode = pNext;
    }
    this.head = pReversedHead;
    return this.head;
  }

/**
   * 查找单链表的中间节点
   * 
   * @param head
   * @return
   */
  public Node SearchMid(Node head) {
    Node p = this.head, q = this.head;
    while (p != null && p.next != null && p.next.next != null) {
      p = p.next.next;
      q = q.next;
    }
    System.out.println("Mid:" + q.data);
    return q;
  }

/**
   * 查找倒数 第k个元素
   * 
   * @param head
   * @param k
   * @return
   */
  public Node findElem(Node head, int k) {
    if (k < 1 || k > this.length()) {
      return null;
    }
    Node p1 = head;
    Node p2 = head;
    for (int i = 0; i < k; i++)// 前移k步
      p1 = p1.next;
    while (p1 != null) {
      p1 = p1.next;
      p2 = p2.next;
    }
    return p2;
  }

/**
   * 排序
   * 
   * @return
   */
public Node orderList() {
	Node nextNode = null;
	int tmp = 0;
	Node curNode = head;
	while (curNode.next != null) {
		nextNode = curNode.next;
		while (nextNode != null) {
			if (curNode.data > nextNode.data) {
				tmp = curNode.data;
				curNode.data = nextNode.data;
				nextNode.data = tmp;
			}
			nextNode = nextNode.next;
		}
		curNode = curNode.next;
	}
	return head;
}

/**
   * 删除重复节点
   */
  public void deleteDuplecate(Node head) {
    Node p = head;
    while (p != null) {
      Node q = p;
      while (q.next != null) {
        if (p.data == q.next.data) {
          q.next = q.next.next;
        } else
          q = q.next;
      }
      p = p.next;
    }

  }

/**
   * 从尾到头输出单链表，采用递归方式实现
   * 
   * @param pListHead
   */
  public void printListReversely(Node pListHead) {
    if (pListHead != null) {
      printListReversely(pListHead.next);
      System.out.println("printListReversely:" + pListHead.data);
    }
  }

/**
   * 判断链表是否有环，单向链表有环时，尾节点相同
   * 
   * @param head
   * @return
   */
  public boolean IsLoop(Node head) {
    Node fast = head, slow = head;
    if (fast == null) {
      return false;
    }
    while (fast != null && fast.next != null) {
      fast = fast.next.next;
      slow = slow.next;
      if (fast == slow) {
        System.out.println("该链表有环");
        return true;
      }
    }
    return !(fast == null || fast.next == null);
  }

  /**
   * 找出链表环的入口
   * 
   * @param head
   * @return
   */
  public Node FindLoopPort(Node head) {
    Node fast = head, slow = head;
    while (fast != null && fast.next != null) {
      slow = slow.next;
      fast = fast.next.next;
      if (slow == fast)
        break;
    }
    if (fast == null || fast.next == null)
      return null;
    slow = head;
    while (slow != fast) {
      slow = slow.next;
      fast = fast.next;
    }
    return slow;
  }