Online Equivalence class

• definition of Equivalence relationship
  1. a   a. (Reflexivity)
  2. a   b if and only if b   a. (Symmetry)
  3. if a   b and b   c then a   c. (Transitivity)
• online equivalence class, also known union-find question.
  1. method 1: use array
     
  2. method 2: stimulate pointer