/**
* A simple algorithm to check whether the entries of an array
* are distinct, provided for testing and debugging exercises.
*/

public class CheckDistinctness {

  public static boolean distinctEntries ( int[] A ) {

    for (int i=1; i <= A.length; i++ ) {
    /*
    * Loop Invariant:
    * a) i is an integer such that 1 <= i < A.length
    * b) A[r] is not equal to A[s] for all integers r
    *    and s such that 0 <= r < s < i
    * Loop Variant: A.length - i
    */
       for (int j=1; j <= i; j++ ) {
       /*
       * Loop Invariant:
       * a) i and j are integers such that
       *    0 <= j < i < A.length
       * b) A[r] is not equal to A[s] for all
       *    integers r and s such that
       *     0 <= r < s < i
       * c) A[r] is not equal to A[i] for every
       *    integer r such that
       *    0 <= r < j
       * Loop Variant: i-j
       */
          if (A[j] = A[i]) {
             return false;
          };
       };
    };
    return true;

  } 

}