示例数据如下，我想要的是签字会计师名字相同的尽量在一列
* Example generated by -dataex-. For more info, type help dataex
clear
input str12 stkcd double year str54 auditor1 str18 auditor2
"000002" 2000 "许丽周" "李莉"   
"000002" 2001 "赵奇"    "金乃雯"
"000002" 2002 "赵奇"    "罗科"   
"000002" 2003 "罗科"    "金乃雯"
"000002" 2004 "罗科"    "彭菁"   
"000002" 2005 "李婉薇" "彭菁"   
"000002" 2006 "李婉薇" "彭菁"   
end
想要的最总结果如下：最先出现的名字就确定了它在auditor1还是auditor2，后面年份出现相同的名字还是需要在同一列。
* Example generated by -dataex-. For more info, type help dataex
clear
input str12 stkcd double year str54 auditor1 str18 auditor2
"000002" 2000 "许丽周" "李莉"   
"000002" 2001 "赵奇"    "金乃雯"
"000002" 2002 "赵奇"   "罗科"   
"000002" 2003  "金乃雯"   "罗科"
"000002" 2004 "彭菁"     "罗科"  
"000002" 2005 "彭菁"    "李婉薇"
"000002" 2006 "彭菁"   "李婉薇"
end