Changes in version 1.2.0 (2019-05-21)                  

  - The efficiency of the classes has been improved.
  - Bugs fixed.

                        Changes in version 1.1.1                        

  - Bugs fixed.
  - A new vignette was added into the package.
  - Every class has the new common method toList.
  - Every class has the new common method is_empty.
  - The insert function of the RBST class can take more arguments.
  - RStack has peek and RQueue has peekleft.

                 Changes in version 1.1.0 (2019-05-14)                  

  - All the functions
  - Documentation including README, LICENSE and etc.