树的深度优先遍历

最新推荐文章于 2024-09-03 01:39:14 发布

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最新推荐文章于 2024-09-03 01:39:14 发布

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文章标签： tree insert null go table

本文链接：https://blog.youkuaiyun.com/sky_blue/article/details/2005270

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下面是直接用深度优先搜索，优点是过程更自然，缺点是效率没有宽度优先搜索高

drop   proc   proc__tree
go

create   proc   proc__tree   (@parent   char(20))
    as
begin
      set   nocount   on
      declare   @level   int   ,@i   int   ,@flag   int
      declare   @stack   table   (parent   char(20),child   char(20),level   int,row   int   ,   flag   int)
      select   @level   =   1,@i=1,@flag=1
      insert   @stack   select   parent,child,   @level,0,1   from       new_tree     where   parent   =   @parent   and   child   is   not   null

      while   @level   >   0
      begin
          if   exists   (select   *   from   @stack   where   level   =   @level   and   flag=1)
          begin
                select   @parent   =   min(child)   from   @stack     where   level   =   @level   and   flag=1
                update   @stack   set   flag   =0   ,   row=@i   where   level   =   @level   and   child   =   @parent   and     flag   =1
                select   @i   =   @i   +1
                insert   @stack   select   parent,child,   @level   +   1,0,1   from       new_tree     where   parent   =   @parent   and   child   is   not   null
                if   @@rowcount   >   0
                      select   @level   =   @level   +   1
          end
          else
          begin
              select   @level   =   @level   -   1
          end
      end
      select   row,parent   ,child,level   from   @stack   order   by   row
      set   nocount   off
end
go
proc__tree   '1'