实现一个单链表，并判断是否有环

最新推荐文章于 2022-08-22 14:24:15 发布

原创最新推荐文章于 2022-08-22 14:24:15 发布 · 429 阅读

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CC 4.0 BY-SA版权

文章标签：

#object #null #interface #class #list

本文介绍了一种基于Java的简单链表实现方法，并提供了一个用于检查链表中是否存在循环的实用函数。通过具体的代码示例，展示了如何添加元素、获取元素及检查循环等基本操作。

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package cn.shine.view;

public class Element {

private Object data;
private Element nextNode;

public Object getData() {
return data;
}

public void setData(Object data) {
this.data = data;
}

public Element getNextNode() {
return nextNode;
}

public void setNextNode(Element nextNode) {
this.nextNode = nextNode;
}

public Element(Object data, Element nextNode) {
  super();
  this.data = data;
  this.nextNode = nextNode;
}

}

package cn.shine.view;

public interface List {
void add(Object o);
int size();
boolean remove(Object o);
Element getElement(int index);
Object getObject (int index);
boolean contains(Object o);
boolean isEmpty();
void clear();
boolean checkLoop();
}

package cn.shine.view;

import java.util.HashSet;
import java.util.Set;

public class LinkList implements List{

Element head = null;
Element tail = null;

public void add(Object o) {
  Element element = new Element(o,null);
  if(head == null) {
   head = element;
   tail = element;
  }
  tail.setNextNode(element);
  tail = element;
}

public int size() {
  if(head == null) return 0;
  Element element = head.getNextNode();
  int size =0;
  while (element != null) {
   size ++;
   element = element.getNextNode();
  }
  return size;
}

public boolean remove(Object o) {
  if(head == null) return false;
  Element nextEle = head.getNextNode();
  while (nextEle != null) {
   if(nextEle.getData() == o) {
    nextEle = nextEle.getNextNode();
    return true;
   }
   head = nextEle;
   nextEle = nextEle.getNextNode();
  }
  return false;
}

public Element getElement(int index) {
  if(head != null) {
   int size = this.size();
   if(index < size-1 && index>0) {
    Element element = head.getNextNode();
    int i = 0;
    while(element != null) {
     if(index == i) {
      return element;
     }
     i++;
     element = element.getNextNode();
    }
   }
  }
  return null;
}

public Object getObject (int index) {
  if(head != null) {
   int size = this.size();
   if(index<size-1 && index>0) {
    Element element = head.getNextNode();
    int i = 0;
    while(element != null) {
     if(index == i) {
      return element.getData();
     }
     i++;
     element = element.getNextNode();
    }
   }
  }
  return null;
}

public boolean contains(Object o) {
  if(head != null) {
   Element element = head.getNextNode();
   while(element != null) {
    if(element.getData() == o) return true;
    element = element.getNextNode();

   }
  }
  return false;
}

public boolean isEmpty() {
  if(head == null) return true;
  return false;
}

public void clear() {
  head = null;
}

public boolean checkLoop() {
  if(head != null) {
   int size = this.size();
   Set set = new HashSet();
   for(int i=0; i<size; i++) {
    Element element = this.getElement(i);
    if(!set.contains(element)) {
     set.add(element);
    }
    if(set.contains(element.getNextNode())) {
     return true;
    }
   }
  }
  return false;
}
}