java模拟实现单向链表

  1 package com.bjpowernode.test.datastructure;
  2 
  3 public class Mylinked {
  4 
  5       Node first;//头结点
  6 
  7       int size;//链表的长度
  8 
  9     public void add(Object value) {
 10         Node newNode = new Node(value);
 11         if (first == null) {
 12             first = newNode;
 13         } else {
 14             Node tmp = first;//当前节点
 15             while(tmp.getNext() != null) {
 16                 tmp = tmp.getNext();
 17             }
 18             //设置最后一个元素的下一个引用
 19             tmp.setNext(newNode);
 20         }
 21         size++;
 22     }
 23 
 24     public void add(Object value,int index) {
 25         Node newNode = new Node(value);
 26         if (index > size - 1) {
 27             //插入链表最后的元素
 28             add(value);
 29         } else {
 30             //在已有的元素之间插入
 31             Node oldnode = first;//头节点,从头结点开始遍历,得到目标位置的元素，后面需要把新节点的next指向它
 32             Node pre = first;//目标节点的上一节点
 33             for (int i = 0; i < index; i++) {
 34                 if (i == index - 1) {
 35                     pre = oldnode;
 36                 }
 37                 oldnode = oldnode.getNext();
 38             }
 39             //需要把上一个节点的next引用指向自己，自己的下一引用指向下一节点
 40             pre.setNext(newNode);
 41             newNode.setNext(oldnode);
 42             size++;
 43         }
 44     }
 45     public Object get(int index) {
 46         Node tmp = first;//当前节点
 47         for (int i = 0; i < index; i++) {
 48             tmp = tmp.getNext();
 49         }
 50         return tmp.getValue();
 51     }
 52     public void remove(int index) {
 53         if (index > size - 1) {
 54             //没有节点
 55             return;
 56         }
 57         if (index == 0) {
 58             //删除头元素
 59             first = first.getNext();
 60         } else {
 61             //找到删除元素的头一个元素
 62             Node tmp = first;//当前节点
 63             for (int i = 0; i < index - 1; i++) {
 64                 tmp = tmp.getNext();
 65             }
 66             tmp.setNext(tmp.getNext().getNext());
 67             size--;
 68         }
 69     }
 70     public void remove(Object obj) {
 71         if (size > 0) {
 72             Node tmp = first;
 73             int k = 0;//表示循环了几次才找到目标对象
 74             while (!tmp.getValue().equals(obj)) {
 75                 tmp = tmp.getNext();
 76                 k++;
 77             }
 78             if (size == 1) {
 79                 tmp = null;
 80             } else {
 81                 Node node = tmp.getNext();
 82                 //需要找到tmp的上一个节点
 83                 Node preNode = first;
 84                 for (int i = 1; i < k; i++) {
 85                     preNode = preNode.getNext();
 86                 }
 87                 preNode.setNext(node);
 88             }
 89             size--;
 90         }
 91 
 92     }
 93     class Node {
 94 
 95         private Node next;//下一节点的引用
 96 
 97         private Object value;//结点值
 98 
 99         public void setNext(Node next) {
100             this.next = next;
101         }
102 
103         public void setValue(Object value) {
104             this.value = value;
105         }
106         public Node(Object value) {
107             this.value = value;
108         }
109 
110         public Node getNext() {
111             return next;
112         }
113 
114         public Object getValue() {
115             return value;
116         }
117     }
118 
119     int length() {
120         return size;
121     }
122 }
123 class Main {
124 
125     public static void main(String[] args) throws Exception {
126         Mylinked mylinked = new Mylinked();
127         mylinked.add("a");
128         mylinked.add("b");
129         mylinked.add("c");
130         mylinked.add("d");
131         mylinked.add("e");
132 
133         System.out.println(mylinked.get(0));
134         System.out.println(mylinked.get(1));
135         System.out.println(mylinked.get(2));
136         System.out.println(mylinked.get(3));
137         System.out.println(mylinked.get(4));
138         mylinked.add("f", 2);
139         //  mylinked.remove(5);
140         mylinked.remove("e");
141 
142 
143     }
144 }