从树上移除子树

Question

 public void removeChild(TreeNode childToRemove)
  {
           if(this.children.isEmpty())
           {
             return ;
           }
           else if(this.children.contains(childToRemove))
           {
               this.children.remove(childToRemove);
               return;
           }
           else
           {
             for(TreeNode child : this.children)
             {
                 child.removeChild(childToRemove);
             }
           }
  }

Answer 1

正如我在评论中所写的，我假设：

• 此方法位于类TreeNode中。
• this.children具有类型list .

即。这是一个基本的树状数据结构。

/**
 * Remove the given node from this TreeNode.
 *
 * @param childToRemove the child to be removed
 * @return true if the child was removed, false otherwise.
 */
public boolean removeChild(TreeNode childToRemove)
{
           // if this tree is empty, there's nothing to do
           if(this.children.isEmpty())
           {
             return false;
           }

           // there's no point checking with "contains", just try
           // to remove the child, and if that succeeds, we're done.
           if (this.children.remove(childToRemove)) 
           {
             return true;
           }

           // the child is not a direct child of this TreeNode, but it
           // may be an indirect child, i.e. a descendant of this node,
           // so we need to try every single descendant in this tree,
           // stopping as soon as we find it to avoid wasting time.
           for(TreeNode child : this.children)
           {
               if (child.removeChild(childToRemove))
               {
                   return true;
               }
           }

           // we couldn't find the node anywhere, so it couldn't be removed.
           return false;
}