数据结构-链表

链表特点

链表是一种用于存储数据集合的数据结构
相邻元素之间通过指针连接
最后一个元素的后继指针值为 NULL
链表的空间能够按需分配
没有内存空间的浪费
链表的长度可以增加或缩小

链表抽象数据类型操作

插入
删除
删除链表
链表长度
查找

链表特点

优点：可以常数时间内动态分配储存空间
缺点：储存和查找数据开销大

单向链表

特点：链表通常指单向链表，包含多个结点，每个结点有一个指向后继元素的 next 指针，表中最后一个结点的 next 指针值为 NULL，表示链表的结束。

单向列表的实现

  public class ListNode {
      private Object data;
      private ListNode nextNode;
  
      public ListNode(Object data) {
          this.data = data;
          this.nextNode = null;
      }
  
      public void setNext(ListNode node) {
          nextNode = node;
      }
  
      public ListNode getNext() {
          return nextNode;
      }
  
      public void setData(Object d) {
          this.data = d;
      }
  
      public Object getData() {
          return data;
      }
  
  
      /***
       * 链表的遍历
       * @return 链表的长度
       */
      public int getListNodeLength() {
          int length = 0;
          ListNode tempNode = this;
          while (tempNode != null) {
              length++;
              tempNode = tempNode.getNext();
          }
          return length;
      }
  
      public ListNode insert(ListNode nodeToInsert) {
          if (this == null) {
              return nodeToInsert;
          } else {
              ListNode temNode = this;
              while (temNode.getNext() != null) {
                  temNode = temNode.getNext();
              }
              temNode.setNext(nodeToInsert);
              return this;
          }
      }
  
  
      /***
       * 在链表中插入结点，分为开头，中间，或者结尾
       * @param nodeToInsert： 插入的结点
       * @param position：位置
       * @return 插入以后的链表
       */
      ListNode insertInLinkedList(ListNode nodeToInsert, int position) {
          if (this == null) {
              return nodeToInsert;
          }
          int size = getListNodeLength();
          if (position > size + 1 || position < 1) {
              throw new PositionInvalidException("Position of node to insert is invalid ,The valid inputs are 1 to " + (size + 1));
          }
          if (position == 1) {   //在链表开头插入结点
              nodeToInsert.setNext(this);
              return nodeToInsert;
          } else {  //在链表中间或者结尾插入结点，需要得到插入位置的前一个位置的结点，同时拿到插入位置的结点，把要插入的结点的下一个结点指向当前位置的结点，前一个位置的结点的下一个结点指向要插入的结点，完成结点的插入操作。
              ListNode tempNode = this;
              int count = 1;
              while (count < position - 1) {
                  tempNode = tempNode.getNext();
                  count++;
              }
              ListNode currentNode = tempNode.getNext();
              nodeToInsert.setNext(currentNode);
              tempNode.setNext(nodeToInsert);
          }
          return this;
      }
  
      /***
       * 删除节点
       * @param deleteNode:需要删除的节点
       * @return
       */
      public ListNode deleteNode(ListNode deleteNode) {
          ListNode listNode = this;
          Object data = deleteNode.getData();
          if (listNode == null) {
              throw new NullPointerException("listNode is empty");
          }
          ListNode tempNode = listNode;
          ListNode previousNode = null;
          while (tempNode != null) {
              if (tempNode.getData().equals(data)) {
                  if (previousNode == null) {
                      listNode = tempNode.getNext();
                      tempNode = null;
                  } else {
                      previousNode.setNext(tempNode.getNext());
                  }
                  return listNode;
              }
              previousNode = tempNode;
              tempNode = tempNode.getNext();
          }
          throw new NodeNotFoundException("This Node is not found in LinkedList");
      }
  
  
      /**
       * 删除链表指定位置的结点,分为从开头删除，中间和结尾删除
       *
       * @param headNode：链表
       * @param position：删除结点的位置
       * @return 删除以后的链表
       */
      ListNode deleteNodeFromLinkedList(ListNode headNode, int position) {
          int length = getListNodeLength();
          if (position < 1 || position > length) {
              throw new PositionInvalidException("position is out of listNode");
          }
          if (position == 1) {  //删除位置在链表开头
              ListNode tempNode = headNode.getNext();
              headNode = null;
              return tempNode;
          } else {  //删除位置在链表中间或者结尾
              ListNode tempNode = headNode;
              int count = 1;
              while (count < position) {
                  tempNode = tempNode.getNext();
                  count++;
              }
              ListNode currentNode = tempNode.getNext();
              tempNode.setNext(currentNode.getNext());
              currentNode = null;
              return tempNode;
          }
      }
  
  
      /***
       * 删除单向链表
       * @param headNode：链表
       */
      void deleteLinkedList(ListNode headNode) {
          ListNode auxilary, iterator = headNode;
          while (iterator != null) {
              auxilary = iterator.getNext();
              iterator = null;
              iterator = auxilary;
          }
      }
  
      /***
       * 打印单链表
       * @return
       */
      @Override
      public String toString() {
          StringBuilder sb = new StringBuilder();
          if (this != null) {
              sb.append("ListNode:(" + this.getListNodeLength() + "){ \n");
              int node = 0;
              ListNode temp = this;
              while (temp != null) {
                  node++;
                  sb.append("  nodeNumber:" + node + ",nodeData:" + temp.getData() + "\n");
                  temp = temp.getNext();
              }
              sb.append(" }");
          }
          return sb.toString();
      }
  }

双向链表

特点
- 比单向列表多一个前驱结点指针
- 插入和删除更加费时
- 添加一个指针，需要额外的空间开销

实现

  		public class DLLNode {
  		    private Object data;
  		    private DLLNode next;
  		    private DLLNode previous;
  		
  		    public DLLNode(Object data) {
  		        this.data = data;
  		    }
  		
  		    public Object getData() {
  		        return data;
  		    }
  		
  		    public void setData(Object data) {
  		        this.data = data;
  		    }
  		
  		    public DLLNode getNext() {
  		        return next;
  		    }
  		
  		    public void setNext(DLLNode next) {
  		        this.next = next;
  		    }
  		
  		    public DLLNode getPrevious() {
  		        return previous;
  		    }
  		
  		    public void setPrevious(DLLNode previous) {
  		        this.previous = previous;
  		    }
  		
  		    /***
  		     * 获取双向链表的长度
  		     * @param headNode：双向链表
  		     * @return
  		     */
  		    public int getDLLNodeLength(DLLNode headNode) {
  		        DLLNode nextNode = headNode;
  		        int length = 0;
  		        while (nextNode.getNext() != null) {
  		            nextNode = nextNode.getNext();
  		            length++;
  		        }
  		        return length;
  		    }
  		
  		    /***
  		     * 双向链表插入
  		     * @param headNode：双向链表
  		     * @param nodeToInsert：待插入结点
  		     * @param position：位置
  		     * @return 插入后的双向链表
  		     */
  		    public DLLNode insert(DLLNode headNode, DLLNode nodeToInsert, int position) {
  		        if (headNode == null) {
  		            return nodeToInsert;
  		        }
  		        int length = getDLLNodeLength(headNode);
  		        if (position > length + 1 || position < 1) {
  		            System.out.println("Position of nodeToInsert is invalid ," + "The valid inputs are 1 to " + (length + 1));
  		            return headNode;
  		        }
  		        if (position == 1) {  //在链表开头插入
  		            headNode.setPrevious(nodeToInsert);
  		            nodeToInsert.setNext(headNode);
  		            nodeToInsert.setPrevious(null);
  		            return nodeToInsert;
  		        } else { // 在链表中间或者尾部插入
  		            DLLNode tempNode = headNode;
  		            int count = 1;
  		            while (count < length - 1) {
  		                tempNode = tempNode.getNext();
  		                count++;
  		            }
  		            DLLNode currentNode = tempNode.getNext();
  		            nodeToInsert.setNext(currentNode);
  		            if (currentNode != null) {
  		                currentNode.setPrevious(nodeToInsert);
  		            }
  		            tempNode.setNext(nodeToInsert);
  		            nodeToInsert.setPrevious(tempNode);
  		        }
  		        return headNode;
  		    }
  		
  		
  		    public DLLNode delete(DLLNode headNode, int position) {
  		        int size = getDLLNodeLength(headNode);
  		        if (position > size || position < 1) {
  		            System.out.println("Position of node to delete is invalid , The valid inputs are 1 to " + (size + 1));
  		            return headNode;
  		        }
  		        if (position == 1) { //删除双向链表的第一个位置
  		            DLLNode tempNode = headNode.getNext();
  		            tempNode.setPrevious(null);
  		            headNode = null;
  		            return tempNode;
  		        } else {  //删除双向链表的位置在中间或者最后
  		            DLLNode previousNode = headNode;
  		            int count = 1;
  		            while (count < position - 1) {
  		                previousNode = previousNode.getNext();
  		                count++;
  		            }
  		            DLLNode currentNode = previousNode.getNext();
  		            DLLNode laterNode = currentNode.getNext();
  		            previousNode.setNext(laterNode);
  		            if (laterNode != null)
  		                laterNode.setPrevious(previousNode);
  		            currentNode = null;
  		        }
  		        return headNode;
  		    }
  		}

循环列表

特点
- 没有结束标志
- 最后一个结点的 next 指向头结点

实现

  public class CLLNode {
      private Object data;
      private CLLNode next;
  
      public Object getData() {
          return data;
      }
  
      public void setData(Object data) {
          this.data = data;
      }
  
      public CLLNode getNext() {
          return next;
      }
  
      public void setNext(CLLNode next) {
          this.next = next;
      }
  
      /***
       * 遍历循环链表
       * @param headNode
       * @return:链表的长度
       */
      public int circularListLength(CLLNode headNode) {
          int length = 0;
          CLLNode currentNode = headNode;
          while (currentNode != null) {
              length++;
              currentNode = currentNode.getNext();
              if (currentNode == headNode) {
                  break;
              }
          }
          return length;
      }
  
      /***
       * 在循环列表最后插入一个结点
       * @param headNode
       * @param nodeToInsert
       * @return
       */
      public CLLNode insertAtEndInCLLNode(CLLNode headNode, CLLNode nodeToInsert) {
          nodeToInsert.setNext(nodeToInsert);
          if (headNode == null) {
              return nodeToInsert;
          }
          CLLNode currentNode = headNode;
          while (currentNode.getNext() != headNode) {
              currentNode.setNext(currentNode.getNext());
          }
          currentNode.setNext(nodeToInsert);
          nodeToInsert.setNext(headNode);
          return headNode;
      }
  
  
      /***
       * 在循环列表的开始位置插入节点
       * @param headNode
       * @param nodeToInsert
       * @return
       */
      public CLLNode insertAtBeginInCLLNode(CLLNode headNode, CLLNode nodeToInsert) {
          nodeToInsert.setNext(nodeToInsert);
          if (headNode == null) {
              return nodeToInsert;
          }
          CLLNode currentNode = headNode;
          while (currentNode.getNext() != headNode) {
              currentNode.setNext(currentNode.getNext());
          }
          nodeToInsert.setNext(headNode);
          currentNode.setNext(nodeToInsert);
          return nodeToInsert;
      }
  
      /***
       * 删除循环列表的最后一个节点
       * @param headNode
       * @return
       */
      public CLLNode deleteLastNodeFromCLLNode(CLLNode headNode) {
          if (headNode == null) {
              return null;
          }
          CLLNode tempNode = headNode;
          CLLNode currentNode = headNode;
          while (currentNode.getNext() != headNode) {
              tempNode = currentNode;
              currentNode = currentNode.getNext();
          }
          tempNode.setNext(headNode);
          currentNode = null;
          return headNode;
      }
  
      /***
       * 删除循环列表的头结点
       * @param headNode
       * @return
       */
      public CLLNode deleteFrontNodeFormCLLNode(CLLNode headNode) {
          if (headNode == null) {
              return null;
          }
          CLLNode currentNode = headNode;
          while (currentNode.getNext() != headNode) {
              currentNode = currentNode.getNext();
          }
          CLLNode secondNode = headNode.getNext();
          currentNode.setNext(secondNode);
          return secondNode;
      }
  }

posted @ 2017-05-07 21:33 熠然阅读(312) 评论(0) 编辑收藏举报

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数据结构-链表

数据结构-链表

链表特点

链表抽象数据类型操作

链表特点

单向链表

双向链表

循环列表

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