Offline Equivalence class

• offline equivalence class, known n and R, get all Equivalence class.
• Two phases to determine equivalence class Phase 1: Equivalence pairs (i, j) are read in and adjacency (linked) list of each object is built. Phase 2: Trace (output) the equivalence class containing object i with stack (depth-first search). Next find another object not yet output, and repeat.
  for (int i = 1; i <= n; i++)  // output equivalence classes 
     if  (!out[i]) { // start of a new class 
               out[i] = true; 
               unprocessedList.push(new Integer(i)) ; 
      while (!unprocessedList.empty()) { // get rest of class from unprocessedList 
            int j = ((Integer) unprocessedList.pop()).intValue(); 
             while  (!list[j].empty()) { // elements on list[j] are in the same class 
                    int q = ((Integer) list[j].pop()).intValue(); 
                    if (!out[q]) { // q not yet output 
                        System.out.print(q + "␣"); 
                        out[q] = true; 
                        unprocessedList.push(new Integer(q));  } //end of if 
                 } //end of while 
              }  //end of while 
          } //end of if