CS 61B lab10

part one parent()

  public TreeNode parent() throws InvalidNodeException {
    // REPLACE THE FOLLOWING LINE WITH YOUR SOLUTION TO PART I.  
      if(!this.valid){
          throw new InvalidNodeException();
      }
      if(this.parent==null)
      return new SibTreeNode();
      return this.parent;
  }

part two insertChild()

 public void insertChild(Object item, int c) throws InvalidNodeException {
    // FILL IN YOUR SOLUTION TO PART II HERE.
      if(!this.valid){throw new InvalidNodeException();}
      SibTreeNode Child = new SibTreeNode(this.myTree,item);
      Child.parent=this;
      this.myTree.size++;
      if(this.firstChild==null){
          this.firstChild=Child;
          return;
      }
      if(c<1){c=1;}
      if(c==1){
          Child.nextSibling=this.firstChild;
          this.firstChild=Child;          
      }else{
          int num=2;
          SibTreeNode CurrentNode=this.firstChild;
          while(num<c){
              num++;
              if(CurrentNode.valid&&CurrentNode.nextSibling!=null){
              CurrentNode=CurrentNode.nextSibling;              
              }
          }
          Child.nextSibling=CurrentNode.nextSibling;
          CurrentNode.nextSibling=Child;
      }
      
  }

part three removeLeaf()

public void removeLeaf() throws InvalidNodeException {
    // FILL IN YOUR SOLUTION TO PART III HERE.
      if(!this.valid){throw new InvalidNodeException();}
      if(myTree.size==1){myTree.size--;this.myTree.root=null;this.valid=false;return;}
      if(this.firstChild==null&&this.myTree.size>1){
           this.myTree.size--;
           if(this.myTree.size==1){this.valid=false;}
           SibTreeNode leafParent=this.parent;
           this.valid=false;
           SibTreeNode CurrentNode = leafParent.firstChild;
           if(!CurrentNode.valid){
               leafParent.firstChild=CurrentNode.nextSibling;
               return;
           }
           while(true){
               if(!CurrentNode.nextSibling.valid){
                   CurrentNode.nextSibling=CurrentNode.nextSibling.nextSibling;
                   return;
               }
               CurrentNode=CurrentNode.nextSibling;
               
           }
           
      }

运行结果：