leetcode 482. License Key Formatting(Key码格式化)(C++和Java)
问题描述: YouaregivenalicensekeyrepresentedasastringSwhichconsistsonlyalphanumericcharacteranddashes.ThestringisseparatedintoN+1groupsbyNdashes. GivenanumberK,wewouldwanttoreformatthestringssuchthateach