用java语言实现单链表

  1 package com.base.list;
  2 
  3 import java.util.HashSet;
  4 import java.util.Set;
  5 
  6 
  7 public class SingleLinkList {
  8 
  9     class Element {
 10         public Object value = null;
 11         public Element nextNode = null;
 12     }
 13     
 14     class Value
 15     {
 16         public String code;
 17         public String name;
 18         
 19         public Value(){}
 20         public Value(String code, String name){ this.code = code;this.name = name;}
 21         @Override
 22         public String toString() {
 23             return code + "-" + name ;
 24         }
 25         
 26         
 27     }
 28     private Element header = null;
 29 
 30     public static void main(String[] args) {
 31         SingleLinkList list = new SingleLinkList();
 32         Value value1 = list.new Value("1", "java");
 33         Value value2 = list.new Value("2", "c++");
 34         Value value3 = list.new Value("3", "c#");
 35         Value value4 = list.new Value("4", "vb");
 36         list.add(value1);
 37         list.add(value2);
 38         list.add(value3);
 39         list.add(value4);
 40         System.out.println("remove vb ?" + list.remove(value4));
 41         System.out.println("have c++ ?" + list.contains(value2));
 42         System.out.println("have vb ?" + list.contains(value4));
 43         System.out.println("list is emptry ? " + list.isEmpty());
 44         System.out.println(list);
 45         list.clear();
 46         System.out.println("list is emptry ? " + list.isEmpty());
 47     }
 48     
 49 
 50     public void add(Object node) {
 51         if (header == null) {
 52             header = new Element();
 53             header.value = null;
 54             header.nextNode = null;
 55         }
 56         Element element = new Element();
 57         element.value = node;
 58         element.nextNode = header.nextNode;
 59         header.nextNode = element;
 60     }
 61 
 62     public void clear() {
 63         header = null;
 64     }
 65 
 66     public boolean contains(Object o) {
 67         if(header==null)
 68             return false;
 69         Element eqEl = header.nextNode;
 70         while(eqEl!=null)
 71         {
 72             if(eqEl.value==o)
 73             {
 74                 return true;
 75             }
 76             eqEl = eqEl.nextNode;
 77         }
 78         return false;
 79     }
 80 
 81     
 82     public String toString() {
 83         int size = this.size();
 84         String print = "";
 85         if(size==0)
 86             return print; 
 87         for( int i = 0; i < size ;i ++)
 88         {
 89             print = "," + this.get(i) + print;
 90         }
 91         print = "[" + print.substring(1) + "]";
 92         return print;
 93     }
 94 
 95 
 96     public Object get(int index) {
 97         if(header==null)
 98             return null;
 99         int size = this.size();
100         if(index > (size - 1) || index < 0)
101         {
102             return null;
103         }
104         Element temp = header.nextNode;
105         int i  = 0;
106         while(temp!=null)
107         {
108             if(index == i)
109             {
110                 return temp.value;
111             }
112             i++;
113             temp = temp.nextNode;
114         }
115         return null;
116     }
117 
118     private Element getElement(int index) {
119         if(header==null)
120             return null;
121         int size = this.size();
122         if(index > (size - 1) || index < 0)
123         {
124             return null;
125         }
126         Element temp = header.nextNode;
127         int i  = 0;
128         while(temp!=null)
129         {
130             if(index == i)
131             {
132                 return temp;
133             }
134             i++;
135             temp = temp.nextNode;
136         }
137         return null;
138     }
139     
140 
141     public boolean isEmpty() {
142         if(header==null)
143             return true;
144         else
145             return false;
146     }
147 
148 
149     public boolean remove(Object o) {
150         if(header==null)
151             return false;
152         Element eqPreEl = header;
153         Element eqEl = header.nextNode;
154         while(eqEl!=null)
155         {
156             if(eqEl.value==o)
157             {
158                 eqPreEl.nextNode = eqEl.nextNode;
159                 return true;
160             }
161             eqPreEl = eqEl;
162             eqEl = eqEl.nextNode;
163         }
164         return false;
165     }
166 
167     public int size() {
168         if(header==null)
169             return 0;
170         Element temp = header.nextNode;
171         int i  = 0;
172         while(temp!=null)
173         {
174             i++;
175             temp = temp.nextNode;
176         }
177         return i;
178     }
179     
180     /**
181      * 检查环状单链表
182      * @return
183      */
184     public boolean checkLoop()
185     {
186         if(header==null)
187             return false;
188         int size = this.size();
189         if(size==0)
190             return false; 
191         Set<Element> set = new HashSet<Element>();
192         for( int i = 0; i < size ;i ++)
193         {
194             Element el = getElement(i);
195             if(!set.contains(el)){
196                 set.add(el);
197             }
198             if(set.contains(el.nextNode))
199             {
200                 return true;
201             }
202         }
203         return false;
204     }
205 }
206